Barrel Wall Thickness Readings
 

While following the GH 16 Damascus wall thickness thread I'm curious what kind of wall thickness readings you normally see on O frame 16 ga factory barrels.

If you own or have measured any what have you found the thickness to be ?

Thanks, Karl

I have 5 or 6 Parker 16’s on the 0-frame, some hammer guns and some hammerless. I have a wall thickness gauge but it is undependable IMO so I won’t use it and post any readings.





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Dean, would you let us know what brand of unreliable wall thickness gauge you are using?

86,7XX, Damascus, 28" DH,0 frame. .028" MWT Both Bbls.
76,5XX, Damascus, 30" Gr. 2 TL, 0 frame. .026" MWT L, .025"MWT R.
59,XXX, Damascus, 28" Gr.2 TL, 0 frame. .025" MWT Both
Eric, Harold, and Allan can comment of the 26" guns they got from me.
If you want 0 Frame, steel barrel MWT, that's gonna take me a while

Bill, it is a Brownell’s. In my experience there is too much flex in the rods.

What is the proper recommended way to use it? I have never had luck with consistent readings.

I never had a problem with a Hosford but I don’t own one. My experience with a Hosford has been with the one formerly at the James D. Julia Auction House.


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I 100% agree with Dean, the gauge from Brownell's is impossible for me to get accurate and repeatable measurements. The rods flex from the slightest pressure in any direction. I use the Galazan wall thickness gauge very heavy and not too portable but accurate and easy to use. Craig

Edgar,

I'm starting to look for a steel barreled 16 O frame and am hoping to get an idea of what to expect as being normal and acceptable .

P.S ... Do you happen to have any recent pictures of Percival for my wife ?

Thanks, Karl

I thought it was just me, but I've had the same experience with the Brownell's gauge. Hard to get the same reading twice.

Personally I would be interested to know what some of these O frame 16 guns measure at the juncture of the chamber and the forcing cone. My apologies to you Karl for my intrusion upon your thread but hopefully you will find this to be useful information to you as well.

That is the most critical area to measure on any classic old sxs. That is the area I would have reported if I had a reliable wall thickness gauge.





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Call it a Clymer, Manson, or Brownell, the gauge is the same. Two things are certain: It's a perfectly reliable tool in the hands of someone who knows how to use it, and, There are a lot of people who don't use it correctly.
I like John Hosford new gauge better than the original version. The 'beam' is either an aluminum investment casting, or CNC machined. The old one(original version, with 1" aluminum tube) is just as good.
When I hear people complain about the perceived lack of rigidity of the rods on a Manson gauge, I am almost certain their technique is lacking.

The barrel must be Horizontal! Whether you're fixing the lugs in a soft jaw vice, or someone is holding them on a table edge makes little difference (unless the table is on a thick rug, the backyard, the beach, or some other soft footing.
Hosford's barrel support rod is the best part of his gauge kit (he will sell them separately) as it allows you to easily rotate the barrel to get readings all around.
Hosford's YouTube video on Zeroing, and using his gauge is very good, and the points he makes are equally true if you're using a Manson (Brownell, Clymer, etc) gauge.
The diameter of the rod inserted into the barrel is the same with all gauges, and has to be small enough to get freely into the bore. My Manson gauge came with a 1/2" rod, and 9/16" ball, so it was too big to measure 28 gauge guns. I simply made a new rod, 7/16", with 1/2" ball.
The eyebolt I added to my gauge, like the ring on the Hosford, makes holding both easy, and repeatable.
The other (lower) rod simply holds the dial indicator, and since the dial is on the bottom side, gravity means it flexes to it's same amount each time.
As long as you're paying attention, and don't allow the upper rod (Same true with Hosford) touch the barrel, you'll get steady, and repeatable readings every time.
Initially, I thought Tony's vertical measuring fixture was the cats meow, but quickly realized it's actually easier to influence the rod deflection, and even fussier to get true, and repeatable results.
I've watch lots of people struggling with zeroing the dial on their indicator. Best way (Take it from someone who has a terrible hand tremor) is to hold the gauge between the ring and EXACTLY AT THE BALL, visually observe it's either at zero, or note the reading, Then hold your thumb on the end of the indicator rod, which prevents the dial from deflection, and rotate to zero.
Because of my tremor, When checking ZERO, I suspend the unit between two points, one at the ball, one at the ring.

Note to that Nit Picking fuss budget (Yeah, You know who you are) who spends more time looking at stuff in the background of my pictures, Bite Me! The Maid is on vacation.

Edgar: Thanks for an explanation I could understand. Got it to work with no issues. I had almost given up on the gauge. Craig

Thanks Edgar - I'll have to take private lessons.

The "maid" told me she refuses to go in there....:corn:





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Nice tip. Now go clean up your room.

Thank you, Edgar. I have explained the correct use of the Manson gauge many times, but it gets lost in the translation. For just over $100, it is the best gauge on the market for the price. You can't take Tony's gauge into a gun show without a "bearer", so it is useless unless you are at home.

Lots of previous discussions regarding wall thickness measurements; here's Bill's protocol
http://parkerguns.org/forums/showthr...?t=7889&page=5
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.

Youtube on how to use the Hosford gage. Part one and two.
http://www.youtube.com/watch?v=1jQZn4kohH4

http://www.doublegunshop.com/forums/...=313266&page=1

I use bungies to affix the barrel in the (weighted with 25# of shot) box in which I carry everything. The barrel is plenty stable, horizontal, and easy to rotate. The owner of the barrel sits to my right (good ear :( ) recording the numbers as a call them out.

http://pic20.picturetrail.com:80/VOL.../413096933.jpg

If I might make a plea, to each of us and esp. dealers, a single MWT number is really not much help without documenting where that MWT was measured. And of little meaning without documenting (muzzle) end of chamber, forcing cone, and at least 9" and 12" numbers.
I've witnessed a dealer running a gauge quickly down (one side of) a barrel, and then pronouncing the barrels "fine" based on the MWT.
OK. Rant over :cuss:

My interpretation of MWT is the Minimum I find, after measuring up, down, and sideways. Meaning, the number I give someone on a gun I might describe, is the thinnest wall thickness I find, Anywhere. Otherwise, it's WT, and not MWT

I measured a honed Smith barrel that was .018" from 14-16". I think the 14-16" part is worth sharing. End of chamber was fine at .106". 9" from breech also inadequate at .032". 9" from muzzle .022".

Measured another honed chain damascus Smith 4E that was .032" 9" from the breech. A dealer reporting that as the MWT without the location would be...uh...worrisome.

Drew, is your "14"-16" measured from the breech or the muzzle?





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Sorry Dean. From the breech.

This is my barrel evaluation template. Nothing proprietary about it so feel free to use. The Word doc is more clear.

http://pic20.picturetrail.com:80/VOL.../414394107.jpg

There is ample space at the bottom for comments ie. DO NOT USE THIS BARREL :eek:

Drew, thank you for repeating my instructions for the "best" method for use of the Manson gauge. It seems a bit wordy, but that was the best I could do. A you-tube video would simplify my instructions if I could ever get around to doing that.

With an assistant, I completed a search of bore measurements and wall thickness measurements of a pair of William Evans sidelock guns at an Alderfer's auction several years ago, using a Galazan bore micrometer and a Manson wall thickness gauge, in about twenty minutes. That included the transcribing of the measurements onto a legal pad. This allowed me to purchase a cased pair of second tier London sidelock guns in high condition for a price that anyone without these measurements wouldn't have had the nerve to purchase at any reasonable price. The guns were perfect, original, no work done on the guns including extending chambers, all bores completely untouched. My tools cost me about $225.00 and I have used them for decades.

:rotf::rotf::rotf:I couldn't help myself, but we've been waiting so long for you to post a picture, a video just seems too good to be true. But, If it did happen, I have no doubt it would get an Emmy :corn::corn::corn: I just love a good movie, and popcorn.

Edgar,

Thanks for getting everyone trained up on taking measurements :bowdown: .... now hopefully we'll get to see some more readings ... :corn:

Mr Spencer and Mr. Hause, thank you both for your explanations. You have cleared up a subject which for me was very muddy.

A manson gauge is very capable of getting accurate thickness measurements.
There is lacks is the limitation of bore size it can measure. As I recall, when I had mine it would not go into a tightly choked 20g. muzzle.
And the size of the ball on the end of the rod does
Not allow measuring into pitted areas as much as a hosford gauge does.
But, for the money, a Manson is a good piece of equipment.

The areas that Drew measures on his record sheet are the areas I like to sample As well. At the forcing cones, around the forend lug (about 9-10” out) and The minimums found out in the second half of the tubes.

Another thought of mine...
The whole wall thickness subject can be a little mirky to
Some as to what is “safe to shoot” and what isn’t.

There are really two ways to look at it. Ultimately one can base their safety conclusions on thresholds of overseas proof house standards. But, anything beyond that is simply based on individual experiences and knowing “well, I have shot other guns with comparable measurements to ‘the subject’ gun, so it should be just fine.
In that type of scenario, different people may have different opinions on what is “thin”.
I have heard people say that they dont like anything with a minimum under .030”. Well, if that is the case, a TON of guns left factories then and now that were/are too “thin”.

Great discussion and explanations. Having just performed these measuring procedures, I am glad that it has been pointed out how to properly zero a gauge (which takes rod flex out of the equation of zeroing), the importance of horizontal zeroing/ gauge use to eliminate gravity's affect on "rod flex" that alters readings, and the importance of not allowing the rods to contact the barrel (or anything else) which would induce rod flex errors. Excellent descriptions!

If someone wanted to make a really, really nice gage for measuring wall thickness, there are woven phenolic materials (rods) available that are super rigid and would possibly suffer little to no flex when used. Further, a notch could be cut on the end of the rod that would allow various screw-in indicator tips to be used instead of a ball on the end which would allow for very accurate measurements of pits or other irregularities in the bores.

A gage made like that would be a bit spendy, however as they say, the right tool for the job is priceless. Here's a picture of various tips that could be used on the end of the rod. I think tips like these are what Brian's referring to..

I will admit that some points Dr. Drew made, got me thinking that I should be taking more measurements to complete the picture. Part of the reason I don't often turn the barrel around and measure in from the breech is laziness due to the manipulation of the barrel, without that extra set of hands. I have always been tuned into those 'improvements' that aren't: chamber lengthening. My preference is towards smaller frame guns, so knowing the wall at the forcing cone is perhaps more important that knowing what the wall is between midway and muzzle. The fore end area is critical to me also, because I have a permanent image in my brain a of guy's thumb tip blown off at a field trial when he let loose to much oomph for the English hammer gun he had only just passed around at show-and-tell.
Brian makes important points, and simply knowing how to properly use the Manson style gauge, and knowing the real numbers, isn't of any value, if you don't also know what numbers are OK, and those that aren't

I especially like the one at the 7 o'clock position.





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Yep, that one and the one at six o'clock could really get down into pits well. The tips at 4 & 7:30 mimic the 'ball' that appears to be on most gages. Having various options would be a nice feature built into a purpose built gage like these.

I considered using a replacement dial indicator tip, which would have required milling a flat on the rod, sufficient such the the dimension from tip-to- back of rod was less than .550”. The whole reason for making the new rod was to measure 28 gauge barrels. Damn tips are more expensive than Harbor Freight dial indicators.
As John Hosford showed in his video, aligning the indicator tip, to the ball is delicate; more so, the smaller the inner tip.
Without question, a finer tip inside the ball will more accurately measure bore pits, however I didn’t anticipate doing barrel evaluations on guns for others, as much as I wanted something for my personal use. I really don’t buy so many guns, and of questionable pitting to offset the smooth needle characteristics given with the .500” diameter ball

The tips would be the cheaper part of the endeavor b/c I'm thinking they would require modification to make them work (ie: the .55 dim you mentioned). It would take a little fine machining to make the working end of the gage work-out just right.

The tips in the photo are Starrett but that's only b/c I buy Starrett everything. There are cheaper alternatives through company's like Enco etc. Also, if one did want to stick with Starrett tips, they can be purchased individually.

My 16 ga. O frame VH has 26" barrels struck 2-15 on the flats, supposedly weighs in at just under 6# (have not personally weighed it). My best efforts indicate .028 MWT both barrels about 12" forward of the chamber's end right along the bottom rib. I use a Galazan tool, results are very repeatable. Only thing wrong with that tool is it should come with wheels and a pull handle.

A couple of thoughts. Yes, rotating the barrel to take readings around the circumference is vitally important. The GH I just sent back was more than thick enough...until I measured adjacent to the bottom rib. Readings became noticeably "thinner", dangerously so, as I got closer to the bottom rib and this was evident throughout most of the barrel length. Had I just measured one zone without considering eccentricity, I would have believed the gun was safe to use.

Pits. There really is no accurate and reliable way to measure the depth of a pit using a gauge. Pits can have minute pores, fissures, etc. All you can do is know that the pit is at least the depth you have measured, and know that it is likely deeper. Pits tend to erode more uniformly with fluid steels since there are no edges of dissimilar metals to follow, but until they are carefully honed out, one can never know.

This is one reason that British proof houses require that all pits be removed by boring or honing, then the bores polished, prior to reproofing. There is also the matter of the tendency of pits to grow with time and humidity, compounded by the fact that it is very difficult to get a pitted barrel truly clean.

I measure lots of (softer than AISI 1010 and up) pattern welded barrels and my 'tip' is brass. I can point it up as needed with use.

http://pic20.picturetrail.com:80/VOL.../406674911.jpg

I agree with Garhart that it is very difficult to a. get into pits and b. know if you are at the bottom of the pit.
Which is also why a full evaluation should include bore visualization with a rigid or fiberoptic bore scope.

Parker barrels are very consistent from the measurements I have taken on my 13 Damascus guns from 10ga to O frame 20ga. All 13 guns are .040 or more at 9 inches and all are .030 plus min. wall except one 12ga #3 frame that was returned to PB with the request "take dent out of barrel". That barrel is has a spot that measures .026. My 6 frame 10ga has a min. wall of .080 in both tubes.
I did purchase a Parker 16 ga that had been honed and had barrels with a min. of .019 and .035 at 9 inches. The .019 was to close to where I hold my left hand for comfort so I sold the gun.
My Fox guns are similar but tend to be very close to .040 at 9" and one tube measures .036 at 9" the gun is very high condition but the bores are .733. Many Fox small bores I have measured and/or owned have min. walls of .025.
I don't feel a need to have them proof tested, but go with the practice shoot shells for which the gun was designed.

Calibrating the Manson/Brownell should be done in a level plane and the 2 points that establish that plane are the anvil ( the measuring point inside the barrel) and the point where the tool is held during use. After the measurements have been taken I check the calibration again to verify that the measurements I have taken are accurate. While i take the wall thickness measurements I repeat the measurement in each position to verify accuracy. Edgar, the pictures of your work area remind me of home on intense days.