Crimp Jump in My M&P340

[BrianE]

I picked up some 158g 38spcl reloads from a friends friend a little while back. I put 50 rounds through my SP101 w/ no issues, but today I put 5 rounds down range w/ 0 issues, then I gave 5 more a try. After the 3rd round the cylinder jammed up. I got the cylinder opened and noticed the bullet was almost out of the case... I thought this was more common with the lighter 357 rounds? Or is this happening due to poor reloading? Im thinking that could have turned ugly...?

Whatcha think?

[Texas1941]

Might well be a light crimp on the reloads. However, very light revolvers have a real issue with bullet jump, even with some factory ammunition. The last Smith owners manual I looked at reccommended testing their light weight revolvers for jump before carrying. Good advise.

It seems to me that a 15 oz or so revolver weight is the point where bullet jump becomes a real issue. Lead bullets seem to be a bit more prone to movement than jacketed bullets, but they will all move unless tightly crimped.

If you reload, just make that your expander is not oversized (this is a big deal) and use a heavy roll crimp on lead bullets that have a crimping groove. For anything else, I use a match grade taper crimp.

All this applies to the 357 as well as the Special.

FWIW,

Charles

[flop-shank]

I could be wrong, but I would expect a good stout FBI load to jump crimp in a scandium snub such as a 340 PD, even if crimped heavily. A jacketed .38+P or .357 such as the Speer SB offerings is the way to go, IMO.

When I briefly danced with masochism by trying to use Remington .357 125 gr. SJHPs in my 360PD, I found that the last round in the cylinder would have jumped crimp a little.

[BrianE]

Texas1941 thank you for the information... I passed it on to the fellow who did the reloading.

I do normally carry it with the Speer GDHP SB 135 38+p, but only shot one cylinder. I was using these as practice ammo.

Just an expensive revolver to just pass on......