20 Gauge Damascus Pressure

[Bruce Day]

Yes. All a person has to do is look at the Parker service load tables and recommended loads to realize that these barrels , whether they be fluid, twist, laminated or Damascus , have way enough hoop strength to use sensible loads. I’m not talking about Black Cloud Prairie Storm guaranteed kill at 100 yards cartridges that manufacturers love to sell at premium prices.

The real issue is whether the barrels have been honed excessively , or if they have deep rust pits , or been whacked hard and cracked. Those issues require a careful examination by somebody with some expertise , not necessarily a gunsmith.

A usually more pertinent issue is recoil and how hard you want the gun to whack the stock or your shoulder. Some 100 year old stocks are solid , others not. And you know that chamber pressure formulas and the recoil formula are related , often confused but very different.

So here are cartridge boxes that I use on Parker small bores Damascus and fluid. The 16 ga ones can be instructive. Using the recoil formula and assuming guns of equal weight , which load produces the least recoil?

While I cannot put the math on here , the variable formula factors are the weight of everything that comes out the muzzle and the velocity of the ejecta. No cartridge length , no stock drop, no chamber angle , no favorite powder brand.

[Drew Hause]

c. 1900 reported 20g pressures vary significantly
7/8 oz. 2 1/2 Dr. Eq. BULK Smokeless was 8000-10,000 psi.
7/8 oz. 2 1/2 Dr. Eq. DENSE Smokeless was 11,000 - 12,500 psi.

Up until about WWI the standard 20g load in the U.S. was 7/8 oz. with 2 1/4 Dr. Eq. Bulk or Dense Smokeless powder at 1155 fps.

As Bruce observed, assuming the barrels are without defects and with adequate wall thickness, using the load listed on the original hang tag would seem reasonable.