doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Modern shotshell out of black powder guns

I've been curious about this for some time. Warnings have been posted not to use modern "smokeless" shells out of black powder proofed guns unless reproofed. However, per the example below, London gun makers were advising their customers on how to load both black powder and smokeless shotshells to be used in the same gun. Curious. What was acceptable then is not acceptable now? (The label is an update to the case applied after some sort of makeover after May 1904)
33243 - 1893
33487 - 1894

I have very little experience with shotguns, but from the rifle side of things it very much can be done provided your smokeless ammo is correctly loaded. In rifles, most factory smokeless loads have a peak chamber pressure that greatly exceeds that of the same case loaded with black powder. Ergo, if you put the factory smokeless ammo into your BP-era gun, you are subjecting it to signficantly more breech thrust and barrel hoop stress than it was originally designed for. If you load your own (or buy from a company that specifically loads nitro for black ammo) it is plenty safe.

I would wager that the same is true for shotguns - modern factory ammo is higher pressure than a BP load, so by shooting the gun with modern factory ammo you are subjecting it to stresses higher than it was designed and proofed for. Some companies load super low pressure shells that are safe in BP-proofed guns, assuming they're in otherwise good mechanical shape.

Early smokeless powders were loaded by volume, like black powder. The accidents started happening when high density propellants came along that required loading by weight not volume. Reilly is giving the shooter the equivalent black powder loads to smokeless. Notice the BP loads are quoted in drams while the smokeless loads are in grains. There’s a lot here in the archives that discusses this at length, ad nauseum etc.

There were multiple reasons makers recommended not shooting nitro in black powder guns and Damascus in particular. First is that nitro ended up being loaded to higher pressures and higher velocities. Maker did not want guns designed for 6,000 psi shooting 8,000+ psi loads. Second there were so many different grades of barrels materials that no one recommendation covered them all. Third if they recommended to not use old guns it stood to reason that you would need to buy new ones. Hence sales drove the advise in part as makers like selling guns and staying in business. The funny thing is that the gun does not care if the powder used is black or nitro. Only the pressures matter in the end.

42 grains "Schultze" or "E.C." = 3 Dr. Eq.
45 grains - 3 1/4 Dr. Eq.

Field, November 26, 1892
https://books.google.com/books?id=inQCAAAAYAAJ&pg=PA296





Pressures were measured using crushers (LUP) and reported in pounds/ sq. inch; modern piezoelectric transducer pressures would be 10 - 14% higher.
12 bore
Nitro 1 1/8 oz. with 42 grain Bulk Smokeless = 3 Dr. Eq. (1200 fps):
5330 - 6110 psi
Nitro 1 1/4 oz. with 45 grain = 3 1/4 Dr. Eq. (1220 fps): 6360 - 8620 psi
16 bore
Service charge 1 oz. 2 3/4 Dram Eq. (1220 fps) = 38 gr. Bulk Nitro powder.
C&H “T.S.” No. 4 BP - 7,480; “Schultze” - 8,250 psi; “E.C.” - 8,960 psi
20 bore
Service charge 7/8 oz. 2 1/2 Dr. Eq. (1210 fps) = 34 gr. Bulk Nitro powder
C&H “T.S.” No. 4 BP - 8,240; “Schultze” - 8,220 psi; “E.C.” - 9,100 psi

Curtis & Harvey “T.S.” (Treble Strong) No. 6 (84 grain = 3 Dr. Eq.) was coarse Black Powder somewhat similar (but not equivalent) to Fg.
“T.S.” was developed in 1871 for the .577/450 Boxer-Henry cartridge used in the Martini-Henry rifle. It was a precursor to “R.F.G.2” (Rifled Fine Grain 2) manufactured at the Royal Gunpowder Mills, Essex, adopted in 1873.
C&H, “T.S.” No. 4 (82 gr. = 3 Dr. Eq.) medium grain similar to FFg
C&H, “T.S.” No. 2 (72 gr. = 3 Dr. Eq.) fine grain similar to FFFg.
https://books.google.com/books?id=mFcCAAAAYAAJ&pg=PA271&lpg
“S.S.” (Smokeless Shot-gun) was a Bulk Smokeless powder made by Smokeless Powder Co. It was discarded as loading with higher charges of powder produced significantly greater pressures than “E.C.” or “Schultze”.

Under the 1896 Rules of Proof
12g 2 1/2” and 2 5/8” chambers (bore .710-.740) for a maximum service load of 3 1/4 Dram Eq. with 1 1/4 oz. shot. (1220 fps)
Definitive Proof – 6 1/2 Drams Proof-House Black Powder with 1 2/3 oz. No. 6 shot = 10,100 psi + 10 - 14%
Supplementary Nitro Proof with 6 1/2 Drams of Curtis & Harvey No. 2 T.S. powder and 1 2/3 oz. shot = 16,400 psi + 10-14%

John Brindle, author of Shotgun Shooting: Techniques & Technology published a review of Proof and Service pressures in Part 5 of his series in The Double Gun Journal, “Black Powder & Smokeless, Damascus & Steel”; Volume 5, Issue 3, 1994, “Some Modern Fallacies Part 5”, p. 11.
He observed that the pressures of the black powder loads in actual use in the 1890s was similar to that of Bulk Smokeless.
Dense Smokeless pressures do run 1000 - 2000 psi higher.

it was the ammo makers much later (in the 1930's I think) that demanded those two warnings be put on shotshell boxes: No nitro in Damascus barrels. And, as we transitioned to the 2 3/4" standard in shotshells, no shells longer than the chamber length. We now know (or have relearned, thanks to Sherman Bell's articles in DGJ) that longer shells in shorter chambers are not necessarily an issue.

re: concern for barrel strength
https://docs.google.com/document/d/1cvqRzkg0wEjhAAcFWr8gFi7aPFRsSIJ_hahfDxmrNAU/edit

To quote John Brindle's summary of the 1891 Proof House report:
“Thus steel had proved stronger than Damascus in this test, but the strength of both was such that this did not matter one bit, such was the margin of safety in a barrel of either material of suitable dimensions and without flaws. And it was the purpose of regular proof tests to find those flaws if they existed.”

A reassuring comment in Sporting Guns and Gunpowders regarding an additional study published in The Field June 6, 1891 by Horatio F. Phillips, a “staff experimenter” with The Field, comparing brazed and unbrazed Steel and Damascus barrels:
http://books.google.com/books?id=inQCAAAAYAAJ&pg=PA14&lpg
These experiments serve to show what a very large margin of strength there is in a good gun barrel, when ordinary charges are used. The (Damascus) barrels which gave way earliest...had withstood the strains of…about four times as great as the regulation proof; while the steel barrels (Siemens-Martin and English “Superior Barrel Steel”) were tested…with charges averaging nearly five times as much as the ordinary proof-charge.
Although the steel barrels showed the greater amount of endurance, the strength of the Damascus was so much in excess of all ordinary requirements that no fear need be felt of their giving way when the work is properly done.