Barrel wall thickness at chokes

[John Havard]

Hello all,

Last night I received a DH 12-gauge with damascus barrels. I purchased it based on three photos from a dealer with hopes that it would be a worthwhile restoration candidate to become a usable shooter. Fairly banged up but a nice ball grip, good wood under the grunge of over 100 years of abuse, and reasonably good engraving.

This morning I pulled out my bore gauge and my Hosford wall thickness gauge and found the following:

Bores were consistently .733" with both left and right chokes at .710", well within what I would have expected although the chambers have been deepened to 2 3/4" (strike one).

Wall thickness through the majority of the barrels was very consistently .034-.040 or more so that, in spite of the scattered pits, seemed okay. However, when checking the wall thickness across the area of the chokes I found that wall thickness only increased perhaps by .010" instead of the .023" suggested by the choke amount (bore of .733" down to choke of .710").

What this makes me guess is that the external barrel walls, especially near the chokes, have been struck a bit, although it absolutely does not show under a magnifying glass when studied closely.

Here's my question for those with insight: can a choke wall thickness of only .040" withstand the forces exerted by the process of constricting a shot column as it is forcibly expelled through the constriction? Or should I send the shotgun back and get my money back?

Thanks in advance for all insights and input.

John

[Dave Suponski]

John, I would be comfortable with those wall thicknesses at the choke. There is very little pressure at the choke end of the barrels. I have a couple of guns with .020 wall at the choke and they have served me fine for years.

[Bill Murphy]

Your calculations are off a bit. A choke of .023 only increases the wall thickness by .0115. Your muzzles are fine and .040 is plenty of thickness through the choke area.

[John Havard]

Doh! Of course you are right Bill! Thanks.

[Richard Flanders]

I have a 26" VH12 with only .017" wall thickness at the muzzle and a +.004" choke in one barrel.... courtesy of a "gunsmith" whose name shall remain anonymous to protect the clearly clueless. The guns works just fine but the muzzles get dented in the wind. I have another gun that I had measured by a reliable smith and was told that there were spots of .009" near the muzzles but I have tried at length and can not duplicate that measurement with my gauge.

[John Havard]

Richard, has it warmed up any today there in God's country? I spoke with my old running buddy down in Kasilof yesterday and even there the temps night before last were minus 20 or colder.

[Richard Flanders]

It has John! It's a toasty minus 9deg at my house right now so it's splitting firewood in a Tshirt time! -37 with light icefog downtown still. A nice inversion has formed. South central Ak is getting their coldest temps in years.... about time I say. They've become pretty spoiled down there.

[John Havard]

The folks in Kasilof don't refer to themselves as living in the banana belt for nothing!

[E Robert Fabian]

John you may find with a letter that your 2 3/4 chambers are origanal, my BH 1905 letters with 2 3/4. Sounds like a keeper.