doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Does Roll Crimping Solve Short Chamber Issues?

I believe he was using plastic hulls and wads with the nitro loads and paper/fiber with the black powder.

HD,

He used Federal and Estate (thinner) plastic hulls with a fiber base-wad, fast burning Clays powder, and a one-piece plastic wad.

JC

Thank you. I though so. Could be interesting if the tests were reproduced with nitro powder and paper hulls. I mean, the warnings of not using long hulls in short chambers couldn't appear out of the blue, and paper shells, being thicker, could have a more marked effect in pressure raising.

After reading Mr. Bell's results I started using 67mm plastic shells loaded to CIP standards
in my Manufrance Id�al with 65mm chambers, proofed to 1,100Kg.
I only recently lengthened its forcing cones and have not yet tried it, but I expect a slightly
lower felt recoil, (though I am not sure I'll perceive it).

JC

HD,

Sorry for the partial answer. Mr. Bell also tests paper hulls (Federal) loaded with one ounce of lead shot,
Clays powder, and a one piece plastic wad.

His results show a lower increase in pressure than the plastic hulls. 602 psi increase at the breech and also at the cone.
As he says, "not enough to worry about". The same test with the longer forcing cone reduces the pressure increase
to less than 100psi at one inch and 100psi at the cone.

JC

He used a variety of hulls, both plastic and paper, and wads, both fiber and plastic. Win AA and Rem hulls as well as Federal. See DGJ, Winter 2001.

Does Sherman Bell have any books printed or just DGJ articles?

Jerry

The original tests on this subject were run many years ago with the introduction of the pie crimp hull. The result was as Rocketman has already stated that virtually all factory loaded pie/fold crimp shells were/are longer than the short chambered guns, "Including Those Certified for use in Those Guns". These tests were all run with paper hulls & card & felt wadding. Bell just re-invented the wheel, it had all been established beginning in the late 1930's & completed immediately following WWII, by the end of the 1940's.
As to the length of the shell in relation to the chamber proper use of a shell longer than the chamber dictates a shell having a pie crimp & a "Loaded Length" very close to a roll crimp hull of same length as chamber. It is decidedly un-wise to fire roll crimp shells in a chamber shorter than the shell, especially if the shell is long enough the end of the loaded shell will be forced into the cone Prior to Firing.

PS; If you want a book which thoroughly discusses this along with about anything else you want to know concerning a shotgun get "The Modern Shotgun" by Burrard

I'd submit that Bell did more than just "reinvent the wheel". Like maybe proved that radial ply tires are a good idea. Indeed, early tests on longer shells in shorter chambers were done with paper hulls and fiber wads. Bell conducted tests with plastic hulls and wads--which meant that those who stated "but those weren't modern plastic shells" no longer had a leg to stand on.

Sherman Bell generated data.