.357 Mag help

[kdm]

Been having issues while reloading 357 mag. First, a little info: all RCBS gear, virgin Winchester brass, Sierra 125 grain JSP bullets.

OK...what's happening is slight case wrinkling, but it's happening in two different ways. First kind of wrinkle looks like the bullet is "over to one side" in the case. There's a slightly raised area on the wall of the case, where the base of the bullet is, for about 180*. Second wrinkle is slight, very slight waves on the area that'd correspond to the base of the bullet.

The two never occur at the same time. Seems like increasing the "belling" of the case mouth decreased both types of wrinkles, but when I seat a bullet I can feel the belled mouth dragging inside the die. When seating, I pull the handle slowly and consistantly...no jamming of the round or anything.

What the heck an I doing wrong?

Also, how much crimp is enough? Any way I can measure to determine, or is it all visual?

[HighLander51]

without further information it sounds like not enough case bell to start.

[LexLuther]

Sounds like bell, or not starting the bullet streight.

[ireload]

I can tell you from experience the Win 357mag case seems to be on narrow side (case interior). The pilot for my RCBS case trimmer had problem with going inside (tight) the case and I was trimming new cases. But when I trim other brands I have no problem. I even tried my Lee case trimmer and experienced the same problem. I trimmed 300 pieces of cases.

Like what others stated -- larger belling. Yes you will feel the case mouth drag on the die wall.

You can probably order thru RCBS a "specific" nose plug for the Sierra JSP bullet. You'll have to send them a sample bullet. I believe some of their revolver dies has a round nose and a semi-wad cutter nose plug already with the die sets.

To me crimping is visual. It's also good to have a uniform lenght of the case so you will have even and uniform crimping. By the way are you seating and crimping at the same time? That can also contribute to the problem.

By the way how is the accuracy of that Sierra JSP? I have the same but in a .38 spl load. I have not loaded any for the .357 mag.

[mjsweims]

You don't say what type of RCBS loader. Have you checked the shell holder, or shell plate (depending on the type of loader) for proper alignment? There may be some dirt in it causing the case to be slightly offset when you get to the seating station..

AFAIK the crimp is visual.

[g17owner]

What types of dies? Carbide or standard? If you you standard and don't lube them what you are describing happens after a few rounds.

[J-cat]

You are starting the bullets in the case mouth crooked and not belling the case mouth enough.

[kdm]

Thanks for the info, guys...lots of good info & help.

Gonna try and do a bulk reply to everyone's questions:

Love the accuracy of the Sierra bullets! Don't have enough info to give a definitive answer, but I can hit the center of a B-27 target at 15 yards 100%. That's with 20.0 of Win 296 and the CCI Mag pistol primers. I'm switching over to Federal 200 primers, so I've dropped my 296 charge down to 19.0...we'll see how things go. Got an old RCBS single stage press. Sizing die is carbide lined. Yeah, the bullet seating/crimping is all in one step.

My next batch of 50 rounds will have larger belling this go-round. I'll let you guys know how it works out. Thanks again!

ETA: OOOH! 311 posts! .311 is a good caliber...303 British, 7.62x39.....

[g17owner]

i seat and crimp in two steps. thiis way i can control the seating and crimp independantly. my old rcbs dies used to do the same thing. win brass is tight as well. try some pmc and see what happens

[kdm]

Thanks, g17...probably gonna go that route. Buddy of mine seats and crimps in separate steps...he's loading 357 up to through 460 S&W, and says he gets better results.

Just loaded up another 50 rounds, this time with lots more case flare. Worked like a charm! No wrinkles, no "off to the side" bumps, no problems. Took a while to set up the seating die, 'cause I wasn't happy with the crimp. (RCBS is quality stuff, except for their !$@$^%$ die lock rings. Pieces of poo. Funny, they recommend putting small lead shot between the set screw and die body...why can't they add 1 cent to the price and provide that? Not everyone reloads shotshells. ) Got some Lyman's split collars a while ago, so I set the die up with that.

Anyway, thanks again for the assist!