doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Minimal barrel thickness and Boss & Co Guns

In my search for a vintage SxS Purdey, H&H or Boss & Co gun I have been told that the minimal barrel thickness I should accept is .025". With that said, I have read numerous accounts of vintage SxS guns from Boss & Co leaving the factory with minimal barrel thickness from .019" to .023". To say the least, I am now confused as to minimal barrel thickness of vintage SxS guns.

I have located a nice vintage Boss & Co "flatback" 12 gauge from around 1895 (gun is stamped "Boss Patent Ejector"). The barrels both have a minimal barrel thickness of .025". Is this a concern as to either the safety of the gun or as to resale value?

Thanks
Ken
kdross@msn.com

Just saw this in Double Gun Classics E-zine

UK recomended minimum wall thickness measured 18" from the barrel breech:
2 1/2" 12g- .028
2 3/4" 12g- .032
Re-proof minimum- .024

From the Griffin & Howe site:
http://www.griffinhowe.com/abbreviations.cfm
"A rule of thumb states that the minimum barrel wall thickness should be .020" in a 12 gauge gun."
No indication if this is 9" or 18" from the breech.

There is no specified wall thickness as far as the rules of proof go. Griffin & Howe's .020" follows the recommendation of the British Gun Trade Association. "Best" guns often had barrels struck on the thin side, to reduce weight. I'd say .025" MWT in a Boss, especially of that vintage, would be quite acceptable.

AS Mr. Brown says, there is no legal minimum thickness and a lot of guns are being shot safely with well under 20 thou mimima. Lightweight Bosses seem to be particularly prone to this, but I know of a pair of Hollands that were recently rebarreled at
17-18 and passed proof handily at that. Someone (I think Greener) did some tests in which barrels were seccessively reamed and shot. It ended when the barrels were so thin they could be cut with a pocketknife. They were still shooting.

Interesting-that came from an interview with Kirk Merrington. I'll try to find the issue and provide a link.

.020" or under, you run the risk of denting your barrels.
A little thicker the better - limb proof!
Things happen in the great outdoors.

OK-found the reference and my increasingly squishy brain didn't quite have it right. The article is about the Manson Wall Thickness Gauge and on p. 56 of Vol 1, No. 4, Jan-Feb 06' those numbers are discribed as the "UK Working Standards for re-proof." Merrington is quoted as being aware of a brl at .010" passing proof.

I have seen barrels pass proof with walls down to 12 thou.

A lot of lightweight guns by Boss, Dickson and others that i have seen were originally made with barrels as thin as 18 thou.


Thin walls will matter more where they are thin. Most guns are thinnest in the section 3-to-8 inches from the muzzles.

Walls or 20 thou will outlast most owners, just don't go bashing them on tractors more often than you need to!

A good pair of sound but thin barrels made that way for a lightweight gun are a different proposition to a pair of originally heavy 19th century barrels that have been repeatedly honed to remove rust and pits. Look at overall condition and regularity as well as minimum thickness.

At .018", a hangnail will dent it.

kdross, along with wall thickness, check the bore dimension. A twelve gauge should nominally be at .729. The original proof marks may have the dimension the bore measured at when it was proofed.

If the barrels are not sound, there's alway Teague.