Trimming 357mag brass shorter?

[2ndAmendmentNut]

I have a Lyman 358429 mould that drops a boolit that is almost to long for my GP100. In fact if I seat them in a freshly trimmed 357 magnum case to the crimp groove they fit exactly flush with the end of the cylinder. Flush with the end of the cylinder is to close for my comfort, so I was thinking would there be anything wrong with trimming the brass a little shorter so that the COL remained normal? I would obviously have to work up max loads with extreme caution do to reduced case capacity, but other then that would there be anything wrong? I am open to other suggestions, but I am personally opposed to loading 357mags in 38special cases.

[cbrick]

That would work just fine, I shorten cases when needed for heavy for caliber boolits in revolvers. Should only take about .010" or so in your case just for insurance against a boolit slipping out a bit under recoil.

Wouldn't hurt to drop the charge 0.5 gr and check for pressure signs.

Rick

[Mallard57]

You could seat and crimp the bullet over the shoulder, I believe I read that's what Elmer Keith did.
Jeff

[cbrick]

Mallard57, that would work of course but that method takes up a lot more powder capacity than just trimming back the brass a bit. 2ndAmendmentNut isn't dealing with a boolit that won't chamber, just looking for a little breathing room.

Rick

[2ndAmendmentNut]

Thank you Mallard57, but Cbrick is exactly right. I already have tried seating the boolit real deep in the case but it reduced the case capacity excessively.

[shotman]

well If you were loading a jacket to max I could see not loading 38 cases but you are loading cast . the 38 case is fine. Some 38 +p cases are built like a 357 ,Winchester head stamp is a heavy wall 38spcl case

[AZ-Stew]

The Keith design is intended to have the front driving band rest in the chamber throat to align the cartridge with the throat/barrel for improved accuracy.

Trimming 5-10 thousandths from the case mouth won't hurt a thing, and I doubt that you'll notice any pressure changes due to "reduced case capacity". There are usually two case lengths listed in handloading manuals for every cartridge, one for max length, the other being a "trim to" length. They almost invariable differ by .010 (ten thousandths). In practical terms, .010 is about the thickness of three sheets of paper. Without doing the math, I'd suspect that's less than a one percent change in case volume, assuming the same bullet seating depth. Not enough to worry about.

P.S. If you're using book loads that are max, but safe in your gun, and are using brass that's never been trimmed to the "trim-to" length, shorten a few to that spec and try your loads. If they're still safe, you should be able to trim all your brass to the "trim-to" length with safety. Your brass should all be trimmed to equal length anyway, to allow you to form consistent crimps. This is essential to accuracy.

Regards,

Stew