Crimping Question

[kramer]

I'm trying to run a RCBS lock out die, bullet feeder and case feeder on my LNL press. I've been using a Lee factory crimp die after the seating die but I'll need to free up a slot for the bullet feeder. What kind of crimp does a Lee seating die use? Roll or taper. I also have a Hornady Custom series II set and it appears to have a roll crimp on the seater die. I thought a roll crimp was a bad idea?

[The_Shadow]

Kramer, is this for 10mm? or other?

If you are loading for 10mm or any other semi auto cartridge you will want seat the bullet fully without any crimp being applied!  If any amount of crimp starts closing the casing walls back against the bullet it can snag and damage the bullet or casing.  I don't like using the FCD as a final crimp die either...

[The_Shadow]

Crimp styles

Straight-------------Wheel Rolled---------------Taper-------------Taper Rolled



---------------------cam crimped-----------------------------------------------

[kramer]

Well I think I may have screwed up a batch of 10mm where I used the seating die to crimp as well. I didn't know it was a roll crimp though I crimped just enough to take the bell out of the mouth.

But I would assume the headspace is toast now right?

[The_Shadow]

It depends on just how much you crimped them.  Measure the very edge of the case mouth, I have seen some crimped down to 0.4180".  The casing with the bullet inside can be expanded to 0.4230" be for applying the crimp, with the expanded case mouth being about 0.4255" for true copper jacket bullet and slightly more for cast and plated.   

Your finished crimps on the very case edge the preferred should measure 0.4215" - 0.4230".

Keep in mind that a cartridge case gauge shows several things, casing that is too big in diameter at any part along the cartridge, it will not fit inside.  If the cartridge is too long it will stick up past the top of the gauge, Brass being too long, bullet seated out too far)

Cartridges that have too short of brass will go too deep inside. (this is not a big issue unless the casing is too long and the crimp is too much)  40S&W will drop down inside of the 10mm gauge because they are 1/8 shorter casing...

[sqlbullet]

And, as a general rule a modern semi-auto pistol actual headspaces on the extractor.  I know SAAMI says case mouth, but functionally the case will almost always stay on the extractor.

The correct method is to just iron out the flare.  Compare a sized, unflared case to a loaded one.  If they are similar, you are good.

Posting a picture would help us a bunch in answering your concern.

[kramer]

Ok I'll post a pic when I get home. I know the case mouth is crimped to .422.

[sqlbullet]

Spec is .423.

.001" won't matter at all.

[my_old_glock]

I'm trying to run a RCBS lock out die, bullet feeder and case feeder on my LNL press. I've been using a Lee factory crimp die after the seating die but I'll need to free up a slot for the bullet feeder. What kind of crimp does a Lee seating die use? Roll or taper. I also have a Hornady Custom series II set and it appears to have a roll crimp on the seater die. I thought a roll crimp was a bad idea?

You could do the crimping in another operation after you loaded everything up. On the first run I usually leave my bullets 0.010"-0.015" higher and I don't crimp. Then after everything is loaded, I remove all the dies except for the seater and crimper. I finish seating the bullets and then crimp. I find I get a more even COAL when the bullet seater isn't competing against the powder measure die and the sizing die.

Some people deprime and resize, and flare, all the brass first. The deprimed brass is then cleaned with stainless media. Then they run the cleaned sized brass through the press. That leave two stations opened; the sizer/decapper and the flare die.


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