Barrel wall thickness

[Thomas L. Benson Sr.]

What is the minimum barrel wall thickness that you would shoot in a 12 Ga. Parker.I would like your feedback and that is shooting RST shells. Considering there is no pitting or damage to the barrels other than just shooting wear.Thanks Thomas

[Chris Travinski]

I guess the biggest question is where the thin spot is, but the industry standard is .025 and most will say .020 isn't a problem if your using RST's. Use your judgment on the condition of the barrels in and out, and for some folks (but not me) the type of steel. For years I shot Remington Express loads out of a 16 ga. with .018" walls, I bought it from a member here who advertised guns for sale in a retail market place and trusted it was safe to shoot. I might not recommend doing that, but it's a good test of Titanic steel barrels.

[Rick Losey]

I often hear 25 thousands mentioned as a standard and I understand in some conditions the Birmingham Proof house will accept 20.

the thinest damascus I have, that I shoot is just with my very own eyes and hands, is a bit over 30.

[Dean Romig]

A reminder that any "minimum" barrel wall thickness you choose to adhere to must be no closer to the breech than 10" - 12" at a minimum.

[Greg Baehman]

. . . I understand in some conditions the Birmingham Proof house will accept 20.
That isn't quite right, in a direct e-mail correspondence I had with the chief inspector of The Birmingham Proof House he says that they will inform their customers when the MWT is thinner than .020, even though the barrels may have passed proof thinner than .020.

[Rick Losey]

That isn't quite right, in a direct e-mail correspondence I had with the chief inspector of The Birmingham Proof House he says that they will inform their customers when the MWT is thinner than .020, even though the barrels may have passed proof thinner than .020.

thanks - at least I said "I understand" not "I know" :)

I still like 30+

[Drew Hause]

http://parkerguns.org/pages/faq/BarrelThickness.htm

I just noticed that the barrel thickness image is missing the source -

The Field March 7, 1891 Vol 77:325

And some more sources that could be added to the FAQ

Christopher Austyn Modern Sporting Guns
"There is no legal minimum thickness for a shotgun barrel, although the British Gun Trade Association recommends 20 thousandths of an inch as a general minimum."

Courtesy of Hugh Lomas for English 12 bore Game guns. Small gauge guns may require additional thickness.
Pre 1925 Proofs:
Chamber Immediately prior to Forcing Cone - .105"
9" from Breech - .045"
4-8" back from muzzle - .025"

Post 1925 proofs:
.100"
.040"
.025-.020"minimum

Michael Lynch, the chief inspector of The Birmingham Proof House, states that they inform customers only if the MWT is below .020" after having passed proof.

George Gibbs Ltd will sell secondhand shotguns with a minimum of .004" of proof size remaining and a minimum of .025" of barrel wall thickness at 9" from the muzzle.
http://gibbsgunmakers.com/Notes%20on%20Proof%20and%20Wall%20Thickness%20of%2 0Shotguns.htm

Courtesy of Austin Hogan
Analysis of 22 twelve gauge Parker barrel sets show the average minimum barrel thickness at 24 inches is .031 inches. Minimum thickness at 18 inches was about .050 inches.
Eccentricity may cause portions of the barrel to be thinner.

[Chris Travinski]

Drew,
What does the minimum of .004" proof size remaining mean?

[Drew Hause]

Based on these standards Chris

http://pic20.picturetrail.com:80/VOL1373/6511424/18059733/383123870.jpg

So if the 12b barrels are marked 729, Gibbs will sell the gun with a bore of no more than .733. If 13/1, no more than .723.

[ed good]

my gunsmith, who has over 60 years of experience, recommends .030 of an inch as the minimum for safe shooting.

[Steve Huffman]

What types of Steel are we talking about here ? All ? Damascus & Fluid ?

[Thomas L. Benson Sr.]

I would consider all types of barrel thickness info important.Thanks Thomas

[Steve Huffman]

What I mean do we use the same minimum for Stub ,Twist, Damascus, Bernard ,Laminated and Fluid steel which is .025" in the forward 2/3 of the barrels length.

[ed good]

personally, i would not consider shooting any non fluid steel barrelled gun with wall thickness less than .040 thousands...and then, only if blessed by someone with far more knowledge of such things than yours truly.

[Steve Huffman]

Ed, Then what is your minimum for fluid steel ?

[ed good]

my gunsmith, who has over 60 years of experience, recommends .030 of an inch as the minimum for safe shooting.

[Joe Wood]

If you set .030 as a minimum there are an awful lot of original Parker's you're not going to shoot. I have three which I'm nearly certain haven't been honed which have walls less than that. I too like the thicker walls but not from fear of a burst but rather because I'd prefer to have extra metal for repairs in case of a dent. Of corse I'm speaking of the forward half or third of the barrel. I'm very critical of having acceptable wall thickness in the first 12". "Acceptable" is a subjective call and the intended ammunition for the gun has a huge bearing on the decision. For instance, I shoot two #1 frames that have from .090 to .095 in front of the forcing cones and that's fine because these are very light upland guns. My duck guns have a lot more armor than that around my hands.

Oh, they're all Damascus.

[Bill Murphy]

My Vulcan Steel ten has minimum wall thickness of exactly .100". Talk about a gun that would drive Sherman Bell crazy!

[David Holes]

Atomic warhead?

[jay shachter]

Hello Guys,

I don't chime in on these conversations often, but the topic keeps coming up. Many know that I own Vintage Firearms, Inc. and buy and sell many Parker guns. Every gun I buy has been measured for minimum barrel wall thickness. In addition, I measure many more sets for others or when contemplating guns to buy for inventory. I measure 300-500 sets of barrels a year. Not all Parkers mind you, but many are. For all I have had through my shop, I have records in spread sheet format that allows me easily to go down a column to see how the numbers fall.

Regarding accepted barrel wall thickness for shooting modern loads, it seems everybody has an opinion. Many of the gunsmiths that render opinions on wall thickness of 25 thou or above work more on modern guns than vintage doubles. If you ask a person who has spent his life working on fine VINTAGE double shotguns, they better understand how these guns were made and have much different opinions on the subject. Most all agree that even 18 thou in the forward half of the barrels is not dangerous from a bursting or bulging stand point, but rather the risk of dents and damage that cannot be repaired as there is not enough metal to work with. More on 18 thou later.

If you ask me, the Brits have been the fussiest about barrels for almost 2centuries, and set the mark for proof testing. Forget opinions based upon everybody bloviating and regurgitating what they have heard or what their friend's opinion is. The British proof houses regularly try and blow up perfectly good guns! They see what barrels can handle by passing not one, but two definitive proof loads through each barrel. I believe the loads are 18,500psi. We all shoot loads that are below 12,500psi (magnum loads), and most of us shoot more reasonable loads that run under 10,000psi. And the guys that have patterned their guns with loads like RST Shells recognize it is not speed that kills, but the nice even patterns premium ammunition provide. RST Shells don't exceed 8000psi. Go to www.rstshells.com for very affordable, safe loads for your beloved doubles.

If barrels with 20 thou wall thickness were regularly failing the proof they would not mention that as the recommended minimum. The facts are that barrels under 20 thou regularly pass proof and are deemed safe. Barrels with 20 thou and all other characteristicds in good shape pass proof in overwhelmingly high numbers. It is extremely rare for failure in the rigid proof testing for barrels in excellent condition because of wall thickness of 18 thou or above. Barrels fail for other reasons, but not often from bursting or changing bore diameters as in bulges. AND REMEMBER, THIS IS WITH 18,500 PSI LOADS!

Doesn't repeated, large sample, empirical testing that occurs in very controlled circumstances trump untried opinions? Especially with DEFINITIVE PROOF LOADS?

The British Gun Trade Association clearly states that 20 thou is the generally accepted minimum for judging healthy guns. This is stated in the Jan/Feb 2012 issue of Shooting Sportsman, and in another Shooting Sportsman article from Sept/Oct 2009 issue. Unless you are shooting guns with obstructions in the barrels, there is no measurable risk shooting reasonable loads in guns with 20 thou wall thickness at least 15" from the muzzle, provided all other issues are sound, like tight ribs, no serious dents, etc. This is not opinion, but data collected for decades under controlled testing.

Now, from my experience I think many Parker collectors and shooters may be surprised that I have measured at least 20 guns that were 20ga. or 16ga. guns on "O" frames that were definitively factory original in the way of blue and bore diameter. They were never backbored or polished inside, and never filed or machined on the outside since leaving the factory, and they had areas 6-12" back from the muzzle that were 18 thou, FROM THE FACTORY. This is almost always in a 3-4" area very close to the top rib or bottom rib, and only on one side of the tube. As one person on this thread mentioned, virtually all vintage American doubles have a very noticeable lack of concentricity, ie thicker on one side than the other. There is also the matter of soldering on the ribs, with the required filing of overflow solder tight in to the rib, creating these thin spots.

All of these guns were very lightweight Parkers. Where most 20ga. Parkers weigh in the neighborhood of 6 1/4lbs., often a few ounces more, how do you think the factory came up with the guns that weigh less than 6lbs. or even 5 3/4lbs.? It is damn hard to hawg a butt and remove 3 oz. of wood. It is usually more like 2 ounces with a lot of hawging. And once hawged out, how do you think they keep the gun from being barrel heavy? They filed metal from the barrels, that is how.

The guns I refer to have been shot for generations, and 10 years ago hunters would regularly use high base shells for everything. After 70-100 years of use they are still unchanged and have perfect barrels.

How many of the opinion makers actually own high quality barrel wall thickness gauges? Not many I can assure you. I travel the country and am surprised how few buyers of fine shotguns own one, let alone know how they are used. If you are going to buy more than a few shotguns in your life, I recommend looking at the Hosford and Co. barrel wall thickness gauge. One mistake in buying a bad set of barrels on an expensive gun will pay for the gauge 5 times over. The Hosford gauge is very convenient and portable. Either that or rely on someone that has one before finalizing any deal in which the wall thickness is not guaranteed by the seller. Just my opinion on that. No dog in the race.

Just examing 100 Parkers I have sold over the last 3 years, 24 of them had at least one of the two barrels with wall thickness under 23 thou. Without a lot of researching each individual gun, I can generally say I don't buy or sell any guns you all would consider unworthy at least as a sound shooter, and in general I have above average shotguns. THAT IS 25% OF THIS SAMPLING THAT PROSPECTIVE PARKER OWNERS WOULD DISMISS IF THEY WERE FOLLOWING THE 25 THOU RULE.

I guess my point is this: It seems there are quite a few folks that come to this forum as being inexperienced with buying and shooting Parkers, and are looking for sound info from members to utilize in getting started shooting and collecting Parkers. Rather than use guesstimates and opinions, why not recognize the results of strict empirical data gathered over the decades of testing provided to us by the Brits? It is certainly better than having fellows looking for a light weight Parker for the uplands simply give up because they can't find one with both tubes over 25 or even 30 thou, as some have stated in this thread. Many of those following that advice would pass over some very fine Parkers for no reason at all. And then they would have to buy Fox guns, as most of them are much lighter than like Parkers! We don't want that do we?

And again, most of the members of our association have no clue what their Parker's barrel wall thickness is. MANY of them are shooting guns that are under 25 thou, and have for decades.

A TOPIC FOR THE NEXT THREAD...CAN SOMEONE FIND THE PRESSURE CURVE DIAGRAM SHOWING HOW A SHOTGUN SHELL DEVELOPS PRESSURE UPON DETONATION, AND AS IT TRAVELS DOWN THE BARRELS UNTIL FINALLY LEAVING THE MUZZLE. I saw that diagram years ago, and it gives a graphic demonstration as to why barrels that are on the thin side forward of the midway point are not at risk of bursting. The entire pressure spike upon detonation occurs in the first 13" or so from the breech, and then is like a pussy cat going down the balance of the barrels. That would help folks understand the physics and mechanics involved.

Sorry for the long post. It is my reason for not writing. I can't say things in a few words while typing!

[Thomas L. Benson Sr.]

Jay: I thank you for a very informative response to my question. I for one wish you would chime in more often. I have learned alot in the time that I have been a PGCA member and having your knowledge is very helpful.Thanks Thomas L. Benson Sr.

[Dean Romig]

Hello Guys,

Unless you are shooting guns with obstructions in the barrels, there is no measurable risk shooting reasonable loads in guns with 20 thou wall thickness at least 15" from the muzzle, provided all other issues are sound, like tight ribs, no serious dents, etc. This is not opinion, but data collected for decades under controlled testing.


From the muzzle Jay or did you mean from the breech?

Thanks for the very knowledgable post. Information like yours is very valuable for everyone who shoots these old doubles.

Was the curve you are referring to printed in Parker Pages or on the forum here someplace?

Dean

[Drew Hause]

This? By DuPont in the mid-30s

http://pic20.picturetrail.com:80/VOL1373/6511424/17126410/314583132.jpg

[Bill Murphy]

I believe that Sherman Bell may have done the "inch by inch" pressure graph for black and smokeless loads. I don't know which one of his articles may have included this information.

[charlie cleveland]

looks like all the powder loads were fairly close in peak preasure.... charlie

[Joe Wood]

Jay, thanks a lot for your input--you clearly stated what I'd feebly tried to say earlier in this thread.

I always carry a wall thickness gauge with me and it has saved my butt several times. One very nice gun offered by a well known dealer and having no visible defects gauged .010! That was a close call! I too am amazed how few dealers have gauges capable of measuring the whole length of the barrel. Do they prefer not to know? Caveat emptor!

[Jerry Harlow]

"This is almost always in a 3-4" area very close to the top rib or bottom rib, and only on one side of the tube. As one person on this thread mentioned, virtually all vintage American doubles have a very noticeable lack of concentricity, ie thicker on one side than the other. There is also the matter of soldering on the ribs, with the required filing of overflow solder tight in to the rib, creating these thin spots."

Jay,

Thanks for the above reply. On almost every set of barrels, this is where I do find the thinnest spots. I had never understood why as one would think this area would not have been the one to meet the file as much as the outermost metal. The tendency is to measure the outside three-fourths of the barrel away from the ribs for thickness and to ignore the one remaining fourth of the barrels for measurement next to the ribs. Now I know why that is where they are the thinnest there. I see it on top more than on the bottom, with lots of low .020 measurements on smaller framed guns.

[Drew Hause]

Possibly 'splaining this. No infro on the load

http://pic20.picturetrail.com:80/VOL1373/6511424/17546456/333454755.jpg

[John Dunkle]

Hello Guys,

I don't chime in on these conversations often,...Sorry for the long post. It is my reason for not writing. I can't say things in a few words while typing!

Jay, I really wish you WOULD chime in more often - excellent post - thank you..!

As a few of you know - I've been following this thread closely for a while, but more recently - hanging on every word for personal reasons. You see...

Recently I put up my DH 20 DAM Parker Show gun for sale (click here if you are a PGCA Member (http://parkerguns.org/forums/showthread.php?t=7875)) and the potential buyer asked me what the barrel wall thickness was? I told him, honestly - I'd never had it checked - and after firing hundreds of RST and my own low pressure rounds through it - never thought to? So, Monday - I did..

To Jay's point about light barrels small bores that left the factory that way, I would agree. Well said! You see, this 26" DAM had an UNSTRUCK weight of 3 pounds exactly (no ounces stamped). Today - after striking and whoever refinished them - they weigh in at exactly 2 lbs - 8.2 ozs, a difference of only 3.8 ozs..

Now - on to the other measurements - bore size (L) is .618 and .619 (R) with constrictions of 0.16 (L) and 0.11 (R). The barrel wall thickness is 0.019 (L) and 0.015 (R) - BUT those are 7.75" from the MUZZLE, not the BREECH..??

So, anyway - I'm wrestling a bit with what to do with this little DH beauty based both on this thread and the collective wisdom posted in this thread regarding wall thickness... Leave it, TIG sleeve, shoot it with removable 28GA tubes - leave the original BBLS as is, etc...???

Hope this helps with the data from my little DH bbls..

John

[Dave Purnell]

Sorry to tell you, John, but there are 12 inches in a foot, but 16 ounces in a pound. Your difference is 7.8 ounces.

Dave

[Robin Lewis]

John,

I was recently told that the TIG process was discontinued and the only liners they are doing now will reduce the gauge size; similar to what others have been doing for years. I have not checked with them directly but the person that told me is very knowledgeable about such things.

[John Dunkle]

Sorry to tell you, John, but there are 12 inches in a foot, but 16 ounces in a pound. Your difference is 7.8 ounces.

DaveThanks Dave!! That's OK - I also messed up the MUZZLE and BREECH, and had to go in and correct that as well..??!! I should learn to type less - or proof read longer :D

Best to you - and thanks again!

John

[Mark Ouellette]

John,

Leave the barrels as they are. Chances are that was how they came from the factory. They are plenty safe for everything except using them to strike rocks!

Just shoot it or sell it. There is nothing wrong with the gun except that it is a lightweight.

Mark

[Steve Huffman]

So John do you still own the 20ga ?

[Joe Wood]

I suggest you keep it as is and disclose the thin walls to any potential buyer (which you already have). That is one beautiful gun! My goodness, how many rounds has it digested in its long life that were probably a heck of a lot hotter than what you've been feeding it.

Remember, WW Greener once had one of his barrels thinned to .010 near the muzzle and then shot proof loads through it with no ill effect. Then he used a pen knife to slit the tubes to show bystanders.

[John Dunkle]

Yes, I still own her. I would NEVER sell something to someone without sharing all I knew. I am so thankful that the prospective buyer asked that I take the barrel dimensions and measurements. I should have done that when I first got her, but I didn't. Its simply a righteous little DH.

So, thanks guys.... I have an aversion to sleeving - especially is it drops her down a bore size. So, I will probably update that "for sale" thread given what I found out - and repost it at a lower price, or - more realistically - just keep her in my safe and shoot it on special occassions with my RST low pressure loads or removible gauge tubes?

My thanks again... Now you know why this thread has been of incredible interest to me....

John

[Steve Huffman]

So what some are kinda saying is some Parkers with Damascus barrels let the factory with 019 thickness we say is unsafe they say was ? Damascus gota Love it. NEVER MIND THIS I WENT BACK AND DID JOHNS MATH !

[Bill Murphy]

Buy a Manson gauge for a hundred bucks and measure the thing to death, John. Advertise it with the measurements you come up with and let them measure it after they send you the check. Have I told you about my friend who bought an absolutley screaming AAHE that was advertised at auction as "under safe wall dimensions" in the auction description? He bought it for about $10,000. It turned out to be an Abercrombie gun that had been ordered to weigh 6 1/2 pounds and was as right as rain. Today it is a $??? gun because of its rarity, originality, and high condition.

[jay shachter]

Thanks everyone for the encouragement. And Dean, I did mean from the breech, not the muzzle. It was Sherman Bell's article, likely in the DGJ. I will do a search as it is something I need for my customers and friends alike. By the way, most are one and the same.

[jay shachter]

Bill M.

Tell me about the Manson gauge, and where can I see one? The problem I had with less expensive gauges was the ability to use them in the field and measure all the way rib to rib. I would like to see if this one would be useful outside the shop.

The reason I like the Hosford gauge compared to the big desk top gauge I had like Galazan sells, or the $150 gauge that I bought from Brownells, is that it is both portable and accurate. 4 different people could use a big desk top gauge we have all seen somewhere, and depending if they tilt the barrel or not, would likely come up with meaningful differences in measurement. Likewise, the only way I could get the little Brownells gauge to be consistent and usable was to hang it stationary from the ceiling and bring the barrels up from below. It was very touchy and difficult to get a good reading.

The Hosford gauge is simple and repeatable, and very portable. With 5 minutes of instruction and practice, 10 out of 10 would get the same measurement within a thou or so.

I hope the Manton is different, as I would like to have another tool!

Thanks again,

The Brow

[Rick Losey]

the Manson gauge

http://www.brownells.com/.aspx/pid=20463/avs%7CManufacturer_1=MANSON%20PRECISION/Product/WALL-THICKNESS-GAUGE

there is a brace that is not shown in the picture that prevents twist

I have practised with it in several modes until I know I can get consistant measurements in different settings.

along with a Skeets bore gauge, a scale, a tape and a caliper (not in the pic) you have a compact set of tools that will give you some level of confidence when you consider a gun.

http://i248.photobucket.com/albums/gg195/setterw/2012-07-12_19-47-53_808.jpg

[Bill Murphy]

Jay, the gauge that Brownell sells for about $100 is the "Manson Gauge". Dave Manson worked with Clymer Reamers and went out on his own and built the gauge that bears his name. The "hanging from the ceiling" method of using the Manson gauge is now old tech and quite inconvenient compared to a method that I was taught by our friend Jon Hosford. Jon realizes that not everyone is a potential customer for his wonderful tool and generously shared this information with me. If there is interest, I will explain it on the forum again as I have in the past.

[Bill Murphy]

The Manson tool can be bought from Dave Manson directly if you choose. His website is mansonreamers.com. The shotgun reamers on the site are very nice items.

[Ken Descovich]

Bill,
Please do. I have one of the $100.00 gauges and am not convinced I am getting accurate measurements.
Thanks,
Ken

[Bill Murphy]

OK, here goes, as Jon explained to me and as I have been using ever since.
1. My gauge has a 5/16" hole in the "block", so I installed an eye bolt in the hole with the eye facing out.
2. I tied a generous loop of clothesline rope to the eye bolt with loops and knots to make holding on easier.
3. You need an assistant if measuring at a gun show or auction. The assistant needs no skill or strength.
4. The assistant will hold the barrels steady on a table with a cushion and the end to be measured over the edge. An assistant is to be preferred over a vise or weights, especially at a show or auction. No weight is heavy enough to hold the barrels steady.
5. The micrometer is zeroed with the rope holding one end horizontally and the ball supported at the other end by the fingers.
6. With the micrometer properly zeroed, the ball end is inserted into the barrel, run from the open end of the barrel to the extent of the rod and the results recorded. The rod must not contact the interior barrel wall for accurate results.
7. The assistant will rotate the barrels on the pad 90 degrees and the results recorded as in the previous instructions.
8. Another 90 degree rotation will complete the measurement of that end of that barrel. The fourth quadrant cannot be measured.
9. Do the same to the other barrel.
10. Reverse the direction of the barrels and do the same from the other end. This should result in 12 recorded minimum thickness measurements from one set of barrels.
11. In my opinion, this procedure, though a bit complicated, is much more convenient and accurate than the old method of hanging the gauge vertically.

[Pete Lester]

John, if I were you I would do as your doing, describe the gun as completely and honestly as you have. If you believe the gun to be in original condition (no evidence or suspicion of honing or reaming) state that too. The gun is going to sell itself, it's unique and it's gorgeous. I am sure you are disappointed, but better to know now up front than have a buyer come back to you later with a potential issue to try to get some money back. I think you are in stronger position for knowing up front.

[Drew Hause]

Sherman Bell's pressure test published in The Double Gun Journal Summer 2002, "Finding Out for Myself, Part VI, Smokeless vs Black", p.19 and summarized in Volume 17: Issue 4, Winter 2006, p. 39

1 1/4 oz. 3 3/4 dram GOEX FFFg Black Powder at 1240 fps and equivalent load Blue Dot
...........................1 inch.................. 6 inches...............12 inches
BP.......................5900 psi...............4100....................2100
Blue Dot...............6000....................4300.... ...............2300

1 1/2 oz. at 1236 fps Blue Dot (weight not stated)
...........................10,000................. 4,400...................2000

[Bill Murphy]

I'm a little surprised about the 10,000 figure, but 1 1/2 ounces is not a friendly load in a 12 gauge at that velocity anyhow.

[Kevin McCormack]

Jay; Jay; Jay!!! -

Your absolutely excellent post looks like a court stenographer's transcription of the wonderful conversation that you, John Hosford and I had at the NE SxS in June! John's gauge paid for itself at about 15X MSRP in the first year I owned it. When dealers see you coming with it, they know whether to give you a little table space to set it up and measure or head for the Porta Potty across the parking lot in double time.

[Steve McCarty]

LOL: I know you guys are purists and love machines that measure things like barrel thickness. That's fine of course.

My method is simplier. I have several old shotguns...maybe half a dozen. I inspect dozens monthly. My method is to peer down the bore and then run my finger down the outside of the tubes. If the bore looks okay and I don't detect any bumps or ripples along the outside then I inspect the muzzles. If they don't look "spooky" thin, and the gun "talks to me", I'll make an offer.

What constitutes "spooky". Well, you've got me, but like pornorgraphy, I know it when I see it.

[Mike Shepherd]

I copied this from a post I made over on the Doublegun BBS:

I sure have a lot of doubles with original chambers and forcing cones with wall thicknesses way below .100" at the end of the chamber.

Fox A grade 16ga, 26" barrels, 2-7/16" chamber, 0.085" and 0.086" minimum wall thickness at the end of the chambers, .734" and .734" diameter at the end of the chambers, 5/8" long forcing cones, #4 barrels, gun weighs 5lbs 9oz, serial 302XXX.

Parker VH O Frame 16ga, 28" steel barrels, serial 134XXX, 2-9/16" chamber, .082" and 0.085" minimum wall thickness at the end of the chambers, 0.730" and 0.732" end chamber diameters, 3lbs 2oz unstruck barrel weight, gun weighs 5lbs 14oz.

AYA #1 20 bore sidelock, factory 2-3/4" (70mm) chambers, 30" barrels, built and proofed in 2006, .092" and .091" minimum wall thickness at the end of the chambers. Skeets gauges unable to measure chamber diameter. Gun weighs 5lbs 13oz.


Fox XE 16ga, 30" barrels, serial 301xxx, .072" and .080" minimum wall at chamber ends, 2-7/16" chambers, .733" and .733" end chamber diameters, gun weighs 6lbs 3oz

Parker DHE 16ga, 32" steel barrels, serial 212XXX, 0.090" and 0.092" minimum wall thickness at chamber ends, 2-9/16" chambers, .735" and .736" diameter at chamber ends, barrel unstruck barrel weight 3lbs 11oz, gun weighs 7lbs 4oz.

Lefever H grade 16 gauge, 28" twist barrels, .090" and .092" minimum wall thickness at chamber ends, 2-5/8" chambers, .729" and .728" diameter at chamber ends. Gun weighs 6lbs 4oz

Ithaca Flues Grade 4E 16 gauge, 28" Krupp fluid steel barrels, 0.091" and 0.092" minimum wall thickness at the end of 2-5/8" chambers, daimeters of .728" and .730" at the end of the chambers, gun weighs 6lbs 6ounces.

Parker DH 12 bore, 28" Damascus barrels, 1 frame, .086" and .090" minimum wall thickness at end of the 2-5/8" chambers, gun weighs 6lbs 14oz. Serial #84XXX, My Skeets gauges are incapable of measuring the diameters at the end of the chamber.

Bissel Birmingham boxlock, 20 gauge, 25" steel barrels, made in the 1920s, .084" and .092" minimum wall thickness at the chamber ends, 2-1/2" chambers. My Skeets gauges are incapable of measuring the diameters at the end of the chamber. Weighs 5lbs 7oz.

[David Holes]

Mike, looks like you have an interesting collection of 16's. Which is your favorite? Dave

[Justin Julian]

This has been a great and informative thread. In that regard, what's the consensus on the safety shooting factor of this DH? I do note that the chamber/forcing cone minimum barrel wall thickness measurements are needed.

http://www.gunbroker.com/Auction/ViewItem.aspx?Item=304446791

[Steve McCarty]

This has been a great and informative thread. In that regard, what's the consensus on the safety shooting factor of this DH? I do note that the chamber/forcing cone minimum barrel wall thickness measurements are needed.

http://www.gunbroker.com/Auction/ViewItem.aspx?Item=304446791

To my eye those barrels look plenty thick. The safety of shooting those fine damascus barrels has been much discussed here. I suggest you find Sherman Bell's articles in Double Gun magazine. He has done extensive research and many tests shooting those damascus/twist tubes. He had a difficult time getting them to let go, even when shooting modern proof loads.

You can also buy lighter loads made specially for the older guns. Look up RST and Polywad shot shells.

Summery, you can find very safe ways to shoot and enjoy guns like these and if in good condition, they are safe when shot with proper loads.

[Mike Shepherd]

Mike, looks like you have an interesting collection of 16's. Which is your favorite? Dave

David I couldn't choose one. The Parker VH 16 and the Fox A grade 16 are neck and neck for my favored Bob White gun. The stock is lower on the Parker and I shoot it a little better.

The Fox XE is a fine gun and maybe the prettiest gun I own. 30" barrels make it nice for dove.

The DHE 16 with the 32" barrels is a great dove gun. A few years ago I took it to Argentina.

I shoot the Flues very well, perhaps better than any other gun I own.

Besides the list above I also have a Parker VHE 16 O frame that weighs 5-3/4 pounds with 26" barrels that I really like. And a Birmy boxlock 16 (Gallyon) the weighs in at 5-9 with 28" barrels that was my first love in double guns.

So I guess the answer is that I don't know.


And thanks!

Mike

[Richard Flanders]

Jay's long response to this question is first class. Factual, logical and to the point. I for one copied it into Word so I can refer to it without having to search for it and show it to friends who might ask the question. Thanks Jay. Very well done.

[Bruce Day]

Back to top. Persons interested might read Jay Shachter's post.

[Drew Hause]

This information was part of a separate thread, but will add it here
http://parkerguns.org/forums/showthread.php?t=10889

Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives (C.I.P) http://www.cip-bobp.org/

Shotgun recommended minimum wall thickness p.4

http://www.cip-bobp.org/sites/default/files/new_file/A-4-1_EN.pdf

For 10 & 12g Standard Steel................................20g Standard Steel

End of chamber - .079”............................................. ....... .075”

Just past the forcing cone/ 4” from breech - .075”................. .071”

8” - .043”............................................. ........................... .041”

12” - .030”............................................. ......................... .028”

16” - .024”............................................. ......................... .022”

20” - .022”............................................. ......................... .020”

FAQ http://parkerguns.org/pages/faq/BarrelThickness.htm

[Bruce Day]

And that correlates to what service and proof loads?

[Drew Hause]

There are three pressure measurement systems (lead crushers/LUP, copper crushers, and piezo), and two standard systems of measure units (USA/SAAMI and CIP/British/European) and two differing units (psi and tons and BAR in kg/cm sq) within each system, different proof laws by country, and differing proof laws by age.
Unfortunately, there is essential NO formula to convert BAR expressed as LUP (CIP) to PSI (SAAMI). LUP + 1000 does not reliably predict the actual piezoelectric transducer measured pressure.

That said, European (CIP) "standard" proof pressure of 850 kg per sq. cm. (BAR) = about 13,920 psi proof pressure = 10,730 psi service pressure (SAAMI)

[Bruce Day]

So are you saying that the commission wall thickness recommended minimums correlate to the commission stated proof loads and service loads? So that if these are the commission recommendations, where do some of the figures that we see thrown out come from? Such as no less than .025 or .030, or pressures no more than 5000psi or 8000psi? I've often wondered where these figures come from and not seen a clear explanation, often its " what is used in England" but what I've seen before it what you published .

[Drew Hause]

Bruce: In the words of Will Rogers "All I know is just what I read in the papers (and on the internet), and that's an alibi for my ignorance."

I'm a bit stunned regarding the .075" recommendation just past the forcing cones :shock:

My NON-EXPERT opinion: It's a lot easier to give pressure recommendations since that information is what shell makers give, when we all know, when using shells for which the gun was originally intended, IN UNALTERED AND INTACT barrels, the primary issue is recoil and the effect thereof on both lock up and the 100 year old wood.

Since the mid-1890s the guns were designed to be used with Nitro Powder

http://pic20.picturetrail.com:80/VOL1373/6511424/17116222/406656956.jpg

Remington Model 1889 "For Nitro Powder"

http://pic20.picturetrail.com:80/VOL1373/6511424/17067005/406313078.jpg

And we know the old boys were using some real boomers :whistle:

Jan. 2 1897
http://www.la84foundation.org/SportsLibrary/SportingLife/1897/VOL_28_NO_15/SL2815017.pdf
Charles Grimm defeats Doc Carver in Chicago for the “Cast Iron Metal”
Grimm used a 12-bore L.C. Smith gun, 7 3/4 pounds, 3 3/4 drams Schultze, 1 1/4 ounce No. 7 shot, in U.M.C. Trap shell.
Carver used a 12-bore Cashmore gun, 8 pounds weight, 4 drams of Carver powder, 1 1/4 No. 7 shot, in U.M.C. Trap shell.

However, very few of us can know what sort of abuse our vintage guns have been subjected to over the last 100 years, the wood is now 100 years old and may well be oil soaked, so prudence might suggest using a Benelli SBE for 3" 1 3/4 oz Fiocchi Golden Pheasant loads like most of the low life philistines with whom I hunt S. Dakota & Kansas pheasants :rolleyes:

[Drew Hause]

Additional commentary regarding the 1891 Birmingham Proof House Trial in Frederick Toms' Sporting Guns and Gunpowder, 1896

'Experiments On the Strength of Gunbarrels' starting on p.9
http://books.google.com/books?id=inQCAAAAYAAJ&pg=PA16&lpg


"These experiments serve to show what a very large margin of strength there is in a good gun barrel, when ordinary charges are used. They also tend to prove that the brazing process (if properly carried out) does not injure the metal to any appreciable extent. It has frequently been alleged, by opponents of the proof test, that, although the barrels may pass through the proof without any apparent injury, yet the large charge strains the metal to such an extent that the barrels are likely to burst afterwards when used with ordinary charges. The fallacy of this argument appears obvious when the fact is taken into consideration that the barrels which gave way earliest under these tests had withstood the strains of nearly thirty successive trials, the first of which was rather more severe than the definitive proof charge, and the average of the whole was about four times as great as the regulation proof; while the steel barrels were tested forty times, with charges averaging nearly five times as much as the ordinary proof-charge.
Taking the cumulative grain test, as calculated in the Birmingham experiments, the strains undergone by each of the two steel barrels were rather over 110 times as great as that of the definitive proof test; and those of the Damascus were rather over 120 times the definitive proof in the case of the barrel that had undergone the brazing process, and nearly 130 times in the barrel that were not brazed. So that, although the steel barrels showed the greater amount of endurance, the strength of the Damascus was so much in excess of all ordinary requirements that no fear need be felt of their giving way when the work is properly done."

https://docs.google.com/document/d/1dnRLZgcuHfx7uFOHvHCUGnGFiLiset-DTTEK8OtPYVA/edit

[Bruce Day]

Regardless we still get people asking here how they can get black powder loads so they can shoot their 1895 Parker damascus and we still get forum participants telling others to keep pressure "low". Of course what they really mean is low recoil for weak stocks but some stocks aren't weak at all. And some tell others to stay under 6000 or 8000psi because that is what damascus guns were designed for , with no authority cited.

Like you I do not feel that these super duper heavy loads are needed, but my point is that these old Parkers are strong guns and built to take some stout loads, then and now.

[Dean Romig]

So we should no longer advise folks to shoot their Damascus guns only with appropriate loads?

[Mike Shepherd]

I contend that a 1925 6-1/2 pound 12 bore Birmingham boxlock was designed to shoot, day in and day out, 1-1/16 oz at about 1,150fps and sub 9,000psi. It was proofed at about 15,000 psi if memory serves. It was stamped by the proof house at 1-1/8oz.

My little Chrysler Crossfire is capable of putting out 215hp and maintaining a top speed of 150mph. But it was designed for , day in and day out, cruising at 80mph and quick but not constant full throttle acceleration.

In the period guns I am interested in the British service load was always less than the maximum load. So a 16 was stamped by the proof house "1oz" but its service load was 7/8oz. A 20 was stamped "7/8oz" but its service load was 3/4oz. The 12 was stamped 1-1/8oz but its service load was 1-1/16 oz. This information is in a table in one of Burrard's three volumes.

[Drew Hause]

Even the lowly Damascus Crescent sold by Sears in 1900 was "Bored For Nitro Powder"

http://pic20.picturetrail.com:80/VOL1373/6511424/20091267/405627118.jpg

re: appropriate loads for which the gun was designed in the inferior Smith guns :)
http://www.lcsmith.org/faq/loads.html

Bruce has posted an image of the Parker recommended loads several times

[Bruce Day]

So we should no longer advise folks to shoot their Damascus guns only with appropriate loads?


Tell them the appropriate loads and pressures that their gun was designed for .
Isn't that something you'd like to know if you were new to Parkers?

[David Hamilton]

Dean, We could go back to the old panic about damasks barrels and advise all to sell all those guns as they are unsafe. We will buy and buy, in the by and by. David

[Dean Romig]

Dean, We could go back to the old panic about damasks barrels and advise all to sell all those guns as they are unsafe. We will buy and buy, in the by and by. David



I'll presume you're being facetious.

Yes, every owner of a Damascus barreled gun, Parker's in this discussion, should be informed of the loads their guns were proofed with, but I don't think we should ever presume to tell them to shoot anything but appropriate loads in their guns because WE have no idea of the condition of the stocks or the barrels of their guns. I would prefer they err on the side of caution rather than throw caution to the wind and shoot "off the shelf" ammo that will fit in their chambers.
I really see no point in discussing this issue further so I'll bow out.

[Rick Losey]

may we also add that the proof was done in original condition and many if not most damascus and even early steel barrels have been "cleaned up"

so what they were proofed for and what they are now safe with are likely two different things. one of my letters states it went back to have barrel work including opening the chokes and back again years later to be "cleaned out", comparing the condition of the outside to the shiny insides when I found it I have no doubt it was done a third time.

all this left a minimum of 30 thousands in the front half. comfortable by most folks standards.

people new to damascus have concerns, they should be taken seriously, then educated

[David Hamilton]

Dean, I do apologize for my facetious remark. No offense was meant. I was only trying to say the same thing you said: This post is exhausted. Sorry, David

[Dean Romig]

Hey David - No apology is necessary.

I completely understood your comment and find no fault with it at all.

I hope I didn't come across as a grouch. If I did I apologize for that.

[Mark Ouellette]

Gentlemen and others,

I am reviving this thread about Minimum Barrel Wall Thickness because that question was asked elsewhere. If you are wondering about minimum barrel wall thickness please read this entire thread for a quick but solid education on the subject!

Mark

[Drew Hause]

We do have more information now that the tensile strength of both pattern welded and fluid steel has been reported. Short version is here
http://www.lcsmith.org/faq/thickness.html

[Mark Ouellette]

Thanks Drew,

We need to incorporate that into facts page of this PGCA site, with your permission of course!

Respectfully,
Mark

[Drew Hause]

Of course :)

I don't want to give everything away before the article, but this is relevant:

Winchester Nickel Steel from Bethlehem Steel Co. Jan. 1900
http://books.google.com/books?id=YzhUAAAAIAAJ&pg=PA181&lpg
Tensile Strength 106,900 psi

Courtesy of Walt Snyder, A.P. Curtis, General Manager of the Ithaca Gun Co. requested composition analysis and tensile strength testing on a section “cut from a barrel made in Belgium” performed by E.J. Stormer, Racine, Wisconsin in 1919. Tensile strength was “about 70,000 psi”.

[Matt Valinsky]

This should be a "Sticky" Please

[Bruce Day]

What is the numerical correlation between barrel tensile strength and barrel rupture psi ? I thought the relevant measurement was psi at rupture as an indicator of ultimate strength

[Bill Murphy]

Deleted

[Drew Hause]

An important but 9 year old thread revived by Bill, then his comment deleted.

I went through each page and unfortunately can not edit nor restore the images.

I'll address Bruce's question in the last post from 2014 then stick to wall thickness measurements

To clarify the issue of barrel strength and wall thickness, tensile strength is only a part of the equation for estimating bursting pressure. There are several burst formula.
All refer to a pipe capped at both ends with a static pressure (a pressure cylinder). UNOBSTRUCTED shotgun barrels are not designed to be pressure vessels as one end is open and the pressure rises and falls quickly SO (according to several mechanical and metallurgical engineers with whom I spoke including Eldon) NONE OF THE FORMULA WORK.

Barlow's formula P=2 S t / D
P=Bursting pressure in psi.
S=Tensile strength of material in tube wall.
t=Wall thickness in inches.
D=Outside diameter in inches.

Burrard used the Alger Burst Formula
Burst pressure = Ultimate tensile strength x 3(OD – ID) / OD + 2xID

The Hoop Stress Formula doesn't reliably predict shotgun barrel failure either
Shotgun barrels are "thin wall cylinders"
σ = pr/t
p= pressure; r is the inside radius; t is the wall thickness

Bottom line is we can't estimate bursting pressure in a properly designed and fabricated barrel, free from internal or external defects.
We do know that it took Sherman Bell >30,000 psi to burst both Parker D3 Damascus and Vulcan Steel barrels


Here's a long thread from last year about measuring wall thickness which has lots of end-of-the-chamber numbers WHICH ARE MUCH MORE CRITICAL than MWT in the distal 1/3 of the barrel.
https://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=615160

More thoughts regarding barrel evaluation & load recommendations
https://docs.google.com/document/d/1ZIo0y746UsSRZIgRuuxwAbZjSBHitO_EanvwLYc-kGA/edit


We now have LOTS more data regarding the actual loads used in our vintage doubles, and Parker Bros. and the other maker's load recommendations. There are several pressure-distance curves also.
https://docs.google.com/document/d/1F2sQuPm05IE4VWYYnCkvuXmYEzQoWd_SQgaAfUOZEFU/edit

BTW Parker Bros. documented as early as 1893 that they proved barrels in-house.

A Parker Service and Proof Load table was published in the 1930s and reproduced in the The Parker Story p. 515. 12g 2 3/4” shell Service Pressure is 10,500 psi. Definitive proof used 7.53 Drams Black Powder and 2 oz. shot with a pressure of 15,900 psi. The pressure was no doubt measured using LUP and modern transducer values would be 10-14% higher, or more than 17,500 psi.

LTC Calvin Goddard reported the same numbers in “Army Ordnance”, 1934. He wrote that Parker followed the SAAMI standards of that period: 13,700 psi proof, 9500 psi service for 2 5/8” chamber; 15,900 psi proof, 10,500 psi service for 2 3/4” chamber (by LUP) + 10-14% for modern transducer measurement.

[Dean Romig]

Deleted


To paraphrase Bill’s post, excessive bore diameter has little relevance without knowing the barrel wall thickness.





.

[Drew Hause]

re: bore measurements
After the proof house revisions of 1887, the British Proof House began using fractional bore

https://photos.smugmug.com/Proof-Marks/i-7LQz6SG/0/1876bdfd/L/British%20Bore-L.jpg (https://drewhause.smugmug.com/Proof-Marks/i-7LQz6SG/A)

So a British 12 bore (and marked '12') could be .729" - .739". If now .740" or > .010" larger than at proof, the barrel is considered out of proof.
The relevance to our U.S. maker's vintage doubles is that a bore greater than expected, esp. with a "mirror" bore, has very likely been honed; making accurate measurements of wall thickness from breech to muzzle imperative.

1954 - 1989 the bore in inches was marked and chamber length in mm, but still with the bore in a diamond.
The bore in inches was dropped in 1989 and replaced with mm.

We also know the factory chamber lengths (which varied over time) of our vintage doubles, and if longer than expected then measurement of the end-of-chamber wall thickness is critical.

[Drew Hause]

Some of the CIP shotshell pressure standards have changed since the 2012 post, and are relevant in that lots of CIP member nation loads are now available
The Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives
https://bobp.cip-bobp.org/en/tdcc_public?page=1&cartridge_type_id=7

https://photos.smugmug.com/Shotshells-and-pressures/Pressure-data/i-Sd2F74f/0/89992caf/XL/CIP%202021%20revision-XL.png (https://drewhause.smugmug.com/Shotshells-and-pressures/Pressure-data/i-Sd2F74f/A)

12g 50mm, 60mm, 65mm, and 70mm “Standard Proof” lead or steel (limited to no larger than 3.25 mm / U.S. No. 4s and max. fps 1,300)
Numbers are transducer BAR converted to PSI.
Maximum Average (SERVICE) Pressure 740 BAR = 10,733 psi;
Maximum Statistical Individual Pressure 850 BAR = 12,328 psi
Mean PROOF Pressure 930 BAR = 13,489 psi
(The original 1984 chart, which was revised in 1990, indicates 12g PROOF 960 BAR = 13,924 psi. The number was revised to 930 BAR)

12g 3” & 3 1/2” “High performance/Superior Proof”
Maximum Average (Service) Pressure 1050 BAR = 15,229 psi
Maximum statistical individual pressure 1200 BAR = 17,405 psi
Magnum proof 1320 BAR = 19,145 psi

12g STEEL regulations: the barrels should carry the High Performance Steel Fleur de Lys stamp and be marked “Steel Shot”

Both 65 and 70 mm 16g standard is SERVICE 780 BAR or 11,313 psi;
MSIP 900 BAR or 13,053 psi;
PROOF 980 BAR or 14,214 psi.
(The original 1984 chart indicates 16g PROOF 1020 BAR = 14,794 psi.
The number was revised to 980 BAR in 2006.)

Both 65 and 70 mm 20g standard is SERVICE 830 BAR or 12,038 psi;
MSIP 950 BAR or 13,779 psi;
PROOF 1040 BAR or 15,084 psi.
(The original 1984 chart indicates 20g PROOF 1080 BAR = 15,664 psi.
The number was revised to 1040 BAR 11-2021.)

[Drew Hause]

In closing ;) this is important.
This illustration was part of the Birmingham Proof House Trial Report of 1891
https://docs.google.com/document/d/1cvqRzkg0wEjhAAcFWr8gFi7aPFRsSIJ_hahfDxmrNAU/edit

https://photos.smugmug.com/Barrel-Evaluations/Barrel-Evaluation/i-wcLrzVG/0/8830b1dd/M/Strength%202-M.jpg (https://drewhause.smugmug.com/Barrel-Evaluations/Barrel-Evaluation/i-wcLrzVG/A)

Three 30” rough bored 12g barrels of 39 different materials (117 total) were received, and the barrels turned and bored to standard dimensions, without cutting the chamber; each barrel was fitted with a breech plug and touch hole and loading was done from the muzzle.
The wall thicknesses do NOT represent standard double gun barrel dimensions.
Note there is no chamber cut nor choke.


For the record, I've found no engineering drawings nor specifications for wall thickness for any U.S. maker. Fortunately now we have LOTS of numbers of presumed unmolested barrels with which to make rational recommendations.

[Craig Budgeon]

Drew my understanding of Britsh proof is that a 12 ga. exceeding nominal size (.729) by more than 010" has to be reproofed before the gun can be sold in England and is marked 12/1 on the barrel flats after successful reproof. Based on that understanding Gibbs would sell a gun with a bore of .735 and is still in proof by .004. Ed Good there would be many Parkers left in dealers gun racks if .030 minimum was the accepted number.

[Drew Hause]

That is correct Craig pre-1954.
1954-1989 the bore would be marked in inches, but I have seen some also marked with the 12/1.

[Craig Budgeon]

Drew, 12/1 can mean reproof, the gun was originally built with barrels which exceeded .739 dia., or that the gun had been rebarreled which is common in England.

[Drew Hause]

Correct, 12/1 = .740" - .750"; if rebarreled prior to 1954
The flats would carry the Crown over R if re-proved.

Interesting collection of proof marks. Originally proved 35-36 by 'P' on the upside-down date code, with '12' and '13/1' (.719" - .728") bore
Then reproved 1959 and marked .729"

https://photos.smugmug.com/Proof-Marks/i-Jp4GPTb/0/4a5837ea/L/Birmingham%20reproof%20KB%3D1959%20%20Joseph%20Asb ury-L.jpg (https://drewhause.smugmug.com/Proof-Marks/i-Jp4GPTb/A)

J. Blanch & Sons original London Proof 1887-1896 with bore 12 (.729-.739").
The time bomb damascus ;) barrels Birmingham re-proved (tiny Crowned R) 1999 (BD) with bore 18.7 mm = .736" which could have been the original bore

https://photos.smugmug.com/Proof-Marks/i-XBsFsBs/0/36954632/M/J.Blanch%26Sons%20BD%3D1999-M.jpg (https://drewhause.smugmug.com/Proof-Marks/i-XBsFsBs/A)