Safe Wall Thickness

[Bruce A Lyons]

About what would be considered a safe wall thickness? Am considering a 16 guage damascus double but wall thickness at muzzle is .022-.025. Is it safe? Thanks

[OH Osthaus]

start here

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


BUT- there is a lot more to a barrel the the muzzle, pressure peaks in the few inches after the chamber, it would be at its least at the muzzle

[Dean Romig]

If you're measuring barrel wall thickness at the muzzle you are measuring choke constriction too. This is a false reading as far as safe barrel wall thickness is concerned.

[B. Dudley]

Wall thickness at the muzzle means little. You need measurements farther back.

[Steve Havener]

Wall thickness should be measured from the breach. Some recommend measuring at 6 inch intervals starting 9 inches from the breach. If I remember correctly the British proof houses will reject any barrels with a thickness less than .025 inches.

[Dean Romig]

Probably the most critical point of wall thickness is where the chamber ends and the forcing cone begins. For instance if a gun was ordered to be 'light as can' or 'light as possible' it would have been built on the smallest frame for the gauge (16 on the 0-frame, 12 on the 1-frame, 10 on the 2-frame) and the barrel filer would have brought the barrels to the minimum. Now, if someone today considers lengthening the chambers.... he better think again.

[Steve Havener]

Originally Posted by Dean Romig

Probably the most critical point of wall thickness is where the chamber ends and the forcing cone begins.

Dean makes a very good point. Today with very good short shells as close as your front door there is no reason to lengthen chambers. If you want to reload getting started is relatively inexpensive. A MEC Super Sizer to resize with, a Lee Load All to de-prime and set primer, drop powder, set wad and drop shot, a beam scale to check powder and shot weight and an antique roll crimp tool to close the shell. All can be picked up reasonably on e-bay.

Load data is not a problem because any load that will fit in a 2 3/4 inch folded crimp shell will fit in a 2 5/8 12 gage shell or 2 9/16th 16 gauge shell with the added advantage of getting the same performance with less chamber pressure using a roll crimp

[B. Dudley]

I always check thickness at front of chambers. At the forend loop. And look for minimum overall in the front part of the tubes. At the very least.

If I am checking and documenting in detail, I check every 4" at top, bottom and side of each tube.

I thought I recall British proof info to be .018" for minimum. ?

I like to see numbers of at least around .025" minimum in the from half. Around .050" to .060" at the forend loop, and I find that most sound barrels run .090" to .100" in front of the forcing cones. These numbers are just ranges that I have found from measuring and firing different barrel sets.

[Bruce Day]

Some of the lightweight British guns were made with thin barrels, around .020 to .022.

Most Parker 12's had original minimum wall thickness from .028 to .040, depending upon desired weight for the gun. In Parker 20's .022 can be original, although most range from .025 to .030.

[King Cobb]

from a very lengthy previous discussion on this forum:

"The Field March 7, 1891 Vol 77:325
http://books.google.com/books?id=inQ...=0#PPA9-IA6,M1



UK Working Standards recomended minimum wall thickness measured 18" from the barrel breech from Double Gun Classics p. 56, Vol. 1, No. 4 Jan-Feb, 2006:
2 1/2" 12g- .028
2 3/4" 12g- .032
Re-proof recomended minimum- .024

The Hunter's Encyclopedia from the German proof house: minimal wall thickness at end of chamber, regardless of length, for 12, 16 & 20 gauge guns should be 2.3mm (.0906") for 'ordinary good steel' or 2.1mm (.0827") if a 'Special Steel' was used. For the 24 & 28 gauges, due to their higher pressures, 2.4mm (.0945") was recommended.
Minimal wall of .6mm (.0236") was recomended in the "forward third" of the barrel. "

Can be found:

http://parkerguns.org/forums/showthr...wall+thickness

also there is another thread where the gentleman who owns vintage firearms Jay, I believe most of what he posted there is in the faq though.

http://parkerguns.org/forums/showthr...?t=7889&page=2