I've been using Lee dies for the last few years for my 44 and 45, with no problems. I dug out an old set of RCBS dies to load some 357 for my Rossi carbine, and I'm having trouble with the crimping.

I first set the seating depth with the die backed out a couple of turns. I then backed out the seating pin and slowly tightened the die until I got the crimp I wanted, a good crimp but not too much. I then ran the seating pin in till it touched the bullet and locked it. I intended to seat the bullet and crimp in one operation.

The crimp isn't like the one I get with the Lee Factory Crimp die. It's like it squeezes the case a little below the case mouth, sometimes shaving a very thin sliver of brass off. Worse, about every 5th case would buckle slightly.

I went back to seating and crimping in seperate operations, but the same thing happens. I seem to remember that I had this problem years ago with this set of dies.

What am I doing wrong?

LT

Take the seating die apart and clean it thoroughly. Be sure the seating plug is clean. Verify whether it is suitable for roundnose or flatnosed bullets.

Be sure to slightly expand (bell) the case mouth prior to inserting the bullet.

When you say you obtain the depth desired, does this mean the case mouth is aligned with the crimping groove in the bullet? Are you using cast or jacketed?

The little thin ring shaved from the case mouth could be caused by excessive crimp. The bulged crimp would also indicate too much crimp.

Lastly, are all your cases trimmed to the same length?

You about covered it kdub. good job. How did it go, crosscut?

Thanks for the help guys.

I've checked most of those things before I posted. I switched to the correct pin before I started. I'm using Winchester HP bullets with the coppor jacket coming up past the crimping groove. The cases were flared. The crimp is in the middle of the crimping groove on this semi-jacketed bullet.

The crimp isn't bulging, the bulge is just below the base of the bullet.

There is very little variation in the case length, maybe .002 or .003.

I guess I'll back off on the crimp, though it doesn't look like too much. Shouldn't a crimp by the RCBS dies look about like one with Lee dies? It doesn't to me. The Lee crimp is more rounded.

LT

Your sizer die reduces the diameter of the case to ensure a good, tight grip on the bullet. It is normal to see a bulge at the base of the bullet when it's seated. The cartridge is now larger where the bullet is seated and at the base where the rim is so it's kind of "wasp" shaped. If the bulge at the base of the bullet is excessive, it can prevent easy chambering or extraction from your carbine so try a few cartridges in you gun before making die adjustments. Too much bulge is an indication of excessive crimp.

Don't know about Lee dies but the RCBS will provide a rounded roll crimp if there is a crimp groove to work with. Your jacketed bullets really don't provide that.

Hijack. Related to Marshal's comment, I just powdered and bulleted 500 rounds of .223, and about every other tray, one round had a large enough diameter that the bullet slid thru the case. I've never had that happen...considering running them back thru the sizing die, I believe I may have neck sized these for the first time ever...if that's a clue.

Marshall,
Maybe "bulge" is the wrong word. I should have said crumpled. The loaded rounds have 2 or 3 wrinkles just below the bullet. They are unusable. The cases are snug enough that you can see the base of the bullet. All these bullete have a cannelure. I'm thinking that the problem may be that the cases are a little too long and that I'm applying too much crimp. I'm not used to these RCBS dies yet.

Thanks for the advice.

LT

Marshall,
Maybe "bulge" is the wrong word. I should have said crumpled. The loaded rounds have 2 or 3 wrinkles just below the bullet. They are unusable. The cases are snug enough that you can see the base of the bullet. All these bullete have a cannelure. I'm thinking that the problem may be that the cases are a little too long and that I'm applying too much crimp. I'm not used to these RCBS dies yet.

Thanks for the advice.

LTI think you're right either the cases are too long or there is too much crimp . Crumpled is not good. Did you set up your crimp as the RCBS directions suggest? If you need help, let me know and will be glad to run through it with you. Think for now you should back off on the crimp and recheck case lengths. Best to have all your cases the same length. When you say the bullets have a cannelure, I take it there is a band of grooves that paralled the bullet axis and not a crimp ring like on lead bullets, right? When you crimp into a cannelure, the crimp cannot be very deep as the bullet jacket is very hard so if you are set up for too much crimp it will buckle the case. It should only take a light push and you should feel the case mouth buckle as the crimp takes place. If you have to apply more force than that, the crimp is too heavy. Hope this helps.