doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Vintage Shell Pressure Summary

Jon;
What is the pump gun? I know that some of the early Marlin pumps were noted as not having strong lock-ups, but don't recall if they were made in 20 gauge or not.

Union Arms Model 50.

Jon;
I have seen a few Union Arms pumps over the years, but have absolutely no personal experience with them. I do not even know how they bolt up.
he only ones I remember in particular as to being somewhat weak are some models of the early Marlins.
Even so, I suspect you are on the right track with the loads you mentioned, I don't think I'd push it too hard.

The early ones had several negative points. One being the side of the action passed over your thumb on the grip when pumped. Get you thumb in the way and you could get a fast cut. The early ones also had a second trigger inside the trigger guard for cocking and decocking the gun. Minor changes were made with the model 50 which eliminated several of the less desirable problems. They never were top of the line but are a serviceable gun for light duty.

I�ve got to look at the lockup system closer to see how strong it is. At first glance it�s better that the early Marlins but that�s a low bar. But to be honest a strong barrel with a decent lockup should be fine. I kind of like clunky actions. They make me appreciate the smoothness of Model12�s, 42�s and 37�s.

Note by 1914 Fox (courtesy of Dave Noreen) and Hunter Arms were recommending only 3 Dr. Eq. loads in 12g



Smith catalog



BTW it was "Ballistite"

Early on "Infallible" was 22 gr. for 3 Dr. Eq. and Ballisite 24 gr. but they were listed as equivalent after about 1902

Thread on Ballistite's creative marketing here
http://parkerguns.org/forums/showthread.php?t=24945

Sporting Life Sept. 1, 1900
J. H. Lau & Co., 75 Chambers street, New York importers and jobbers of firearms, ammunition, sporting and fencing goods, are sole agents for Nobel's sporting Ballistite smokeless shotgun powder. This powder has been very extensively introduced in this country and has gained for itself a place among the leaders. It is a smokeless, waterproof powder, combining uniformity and accuracy, high velocity, small bursting strain, no residue, no leading of the barrels and perfect safety, owing to its being unaffected by climatic changes. Its quickness of combustion recommends it to all users of smokeless powder. The recoil is slight even with the maximum charges.

Nov. 15, 1902
J. H. Lau & Co., 75 Chambers street, New York, importers and dealers in firearms, ammunition and fencing goods, are sole agents for Nobel's Ballistite powder. They claim for the sporting Ballistite powder quietness, high velocity and penetration, smokeless and clean.

Feb. 18, 1905
The Ballistite powder still maintains a popularity among trap shooters owing to its high velocity, quickness and low bursting strain. "Shooting Facts" will fully describe Ballistite powder and give much important and interesting matter to shooters. J. H. Lau & Co., 75 Chambers street, New York, will supply this book free of cost.

Thanks for that extra but of data. So standard 20 load would be 2 1/4 drams with 7/8!ounce shot. Any idea of pressures to expect from those loads? Perhaps I�ve set my pressure levels artificially low.

20g pressures

�Experiments by Mr. R.W.S. Griffith of the Schultze Powder Co.� in Sporting Guns and Gunpowder
https://books.google.com/books?id=inQCAAAAYAAJ&pg=PA38&dq
Converted using Burrard's formula
7/8 oz.
66 gr. C&H T.S. No. 2 BP = 2.4 Drams = 8,300 psi
33 gr. "E.C." Bulk = 2.36 Dr. Eq. = 8,300 psi
22 gr. Dense Walsrode = 2.38 Dr. Eq. = 10,750 psi

William Bruette, Guncraft: Guns, Ammunition, Wing & Trap Shooting, 1912
https://books.google.com/books?id=5g51K93as84C&pg=PA210&dq
Converted using Burrard's formula
Amberite 2 1/2� case 2 1/3 Dr. Eq. 13/16 oz. = 11,648 psi
Curtis & Harvey�s Smokeless Diamond 2 1/2� case 2 1/3 Dr. Eq. 13/16 oz. = 12,320 psi

c. 1920 DuPont Ballistic Table on the 1st page
2 1/2 Dr. Eq. 7/8 oz = 12,655 + 10%
2 1/4 Dr. Eq. 3/4 oz. = 9,900 + 10%

For years I did not know what the difference in Infallible & Unique was. Some statements seemed to indicate they were identical. If so, Why did they sell both? Early loading data listed only Infallible for shotguns with Unique for pistols & light rifle loads. Infallible was eventually dropped & Unique began to be recommended for shotshells as well.

Finally, I found out the difference. Both powders had the exact same chemical composition & both were a flake type powder having the same diameter of round flakes. Infallible flakes were .3mm (.012") thick while Unique flakes were .35mm (.014") thick, thus Infallible was just a wee bit faster & also a bit easier to ignite with early shotshell primers.

I found this in an old American Rifleman article on shotshell propellants.