Barrel wall thickness
 

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

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.

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.

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.

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+

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...20Shotguns.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.

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

Based on these standards Chris

http://pic20.picturetrail.com:80/VOL.../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.

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

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

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

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.

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.

Ed, Then what is your minimum for fluid steel ?

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

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.

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

Atomic warhead?

barrel wall thickness
 

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!

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.

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

This? By DuPont in the mid-30s

http://pic20.picturetrail.com:80/VOL.../314583132.jpg

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.

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

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!

"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.

Possibly 'splaining this. No infro on the load

http://pic20.picturetrail.com:80/VOL.../333454755.jpg

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) 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

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

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.

Thanks 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

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

So John do you still own the 20ga ?

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.

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

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 !

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.

barrel wall thickness
 

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.

barrel wall thickness gauge
 

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