Wall Thickness Gauge

[Hammer Gun]

Dean, It seems hard to get an exact measurement from one of these gauges when you are holding one end with your hand and guiding it through the barrels. seems the chance of moving the gauge inadvertently up or down or sideways would skew the results, also seems the weight of the arm albeit very small would make a couple thousands difference. It seems you would need a "guide to put in the muzzle end of the barrel to keep it in the center and give a much more accurate read and not be subject to hand movement, but I do not own one of these gauges so have just seen them demonstrated at Deep River, Gary

[Opening Day]

Originally Posted by Gary Carmichael Sr

Dean, It seems hard to get an exact measurement from one of these gauges when you are holding one end with your hand and guiding it through the barrels. seems the chance of moving the gauge inadvertently up or down or sideways would skew the results, also seems the weight of the arm albeit very small would make a couple thousands difference. It seems you would need a "guide to put in the muzzle end of the barrel to keep it in the center and give a much more accurate read and not be subject to hand movement, but I do not own one of these gauges so have just seen them demonstrated at Deep River, Gary

Gary, you do not hold the barrels with your hand, you place the barrels on the mandrel that comes with the gauge, the only part of your hand that you use is your one finger to slide the gauge down the bore, if you are doing it any other way it's the wrong way...

Is this gauge expensive, yes but if I had had it before a certain auction I would not been stuck with a gun that the auction house said was thirty thousands and it turned out to be fifteen a very expensive mistake on my part so it can pay for it's self in one use !

[Brush Buster]

I do own one of the Hosford gauges and measure BWT on most every gun I purchase ,as stated if you in fact move your guiding arm up or down it changes measurements decidedly but if you take your time and watch as you guide it down the bore over and over you can come up with very similar results with each measurements ! To be quite honest , it is an enjoyable task but mostly what I use my gauge for is pitting , it is very easy to look down the bore and see a pit but you have no way of knowing how large or especially how deep it extends into the wall of the barrel ! These gauges are great for this type of measuring ,the head will drop directly into the pit and without any doubt you know instantly how deep it is ! The gauges are expensive but so are Higher Graded Parker Guns and much more so if the Barrels are bad and you are stuck with it !!!!!!!!!!!!!!! When I buy any gun ,especially on line I always request at least a three day inspection and return period and this time is used to measure the BWT , it is most helpful with the Damascus Barreled guns which seem to have the most pitting ,probably because of the age of the gun and the powders burn't in them early on ! I feel the Gauge is money well spent , but it is Just my Two Cents worth of opinion !

[Dean Romig]

Right Russ, and the corrosive primers of the day as well.





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[Drew Hause]

Using a wall thickness gauge is not difficult, but takes time, and is a 2 man job; one manipulating the gauge and the other to rotate the barrels (because of eccentricity) and record results.
One word of warning.
I've measured refinished barrels with bores at the expected factory dimensions, but the exterior of one 16g barrel had been filed to remove pits, and the wall thickness was .016”, 14” from the breech. It had survived 250 2 1/2” Polywad Spred-R shells, 100 2 1/2” 7/8 oz. at 1145 fps. (about 8000 psi) loads, and 2 cases (500 shells) of 2 1/2” RST 3/4 oz. at 1100 fps (4,600 psi per RST) without rupture or dimensional changes.

And at the risk of repeating myself a dealer reporting "MWT is ____" is totally inadequate

[OH Osthaus]

Originally Posted by Dean Romig

Right Russ, and the corrosive primers of the day as well.
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correct - black powder often takes the blame for the damage the corrosive primers did- many guns from the 20th century that never saw BP show pits-

all due to the primers

I have a Manson gauge - certainly not the quality of the Hosford - and not the price- it took practice - but i can get repeatable measurements - the biggest drawback is the tip is round and will not go in a pit

i have wondered if replacing it with a 60 degree tip as I use for bamboo planning forms would do it

[Dean Romig]

That would make perfect sense Rick.





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[Kensal Rise]

One might get away with this philosophy in regard to American built guns like the Parker, Fox, L. C. Smith, etc.

Their barrels generally run a bit "thick" to begin with. Thus a hone or two might not be dangerous.

However, do NOT count on this approach with British or European guns. Especially those from the 19th or 20th centuries. Their barrels were often turned to a thinner overall wall thickness/contour to begin with. Thus, a bore gauge might suggest "OK" after honing, but the actual wall thickness could well be below safe limits.

It is also important to know where a barrel might be thin. Anything odd within the first 18 inches is vital to know about.

To paraphrase Gen. Douglas MacArthur, "there is no substitute for wall thickness."

[Drew Hause]

Nice of the Belgians to tell us exactly the bore and muzzle constriction, weight of the barrels at time of proof, and load (only 1897-1903) for which the gun was designed.

12g Manufacture Liegeoise likely proved with Mullerite for a service load of 2.70 grams = 41.67 grains = 3 Dr. Eq. (42 grains) "E.C." No. 1 or "Schultze" with 36 grams = 1 1/4 oz. shot.
Note bore 22 cm from breech was 18.2 mm = .716". After WWI bores were generally 18.4 = .724"; honed to .729" would only be a loss of .0025" of barrel wall IF perfectly concentric.
If originally .716" and honed to .730" would be loss of .007" barrel wall.

[Bill Anderson]

[QUOTE=John Campbell;205811]One might get away with this philosophy in regard to American built guns like the Parker, Fox, L. C. Smith, etc.

Their barrels generally run a bit "thick" to begin with. Thus a hone or two might not be dangerous.

However, do NOT count on this approach with British or European guns. Especially those from the 19th or 20th centuries. Their barrels were often turned to a thinner overall wall thickness/contour to begin with. Thus, a bore gauge might suggest "OK" after honing, but the actual wall thickness could well be below safe limits.

It is also important to know where a barrel might be thin. Anything odd within the first 18 inches is vital to know about.

To paraphrase Gen. Douglas MacArthur, "there is no substitute for wall thickness."[/QUOTE

Good point to remember, but for me personally, I have never even looked at a British gun, let alone have any desire to own one.

Bill