Crimping 5.56 x 45

[Blitzfike]

Dennis
I should have been more specific. What I meant was I was wondering if using the Lee crimper messed up the brass any with its specific crimp technique.
I have used a slight roll crimp on some of my pistol ammo. I usually don't crimp pistol ammo but have in the past put a slight roll
Crimp on some ,45 and 9mm used in semiautos. I too have never had a problem using a roll crimp and have never crushed any cases that way.
In your competition shooting are you shooting semiautos or other rifles?

I should have been more specific, I'm referring to auto pistols and headspacing on the case mouth. Again, that only applies to straight wall cases, not bottleneck cases like the 7.62X25 or the few other bottleneck pistol cases.

 

[Repubiman]

You all are correct. Forgive me for saying I roll crimped my pistol cases when I actually put a
slight "taper crimp" on them.
I use RCBS dies and the instructions clearly state that it is a taper crimp and not roll crimp as
I mistakenly called it. So to correct myself as was pointed out, I have put a slight taper crimp
On some of my pistol ammo for my semiato pistols. Sorry for any confusion.

 

[Blitzfike]

Taper crimp is great for semi autos, the biggest cause of fail to feed in semi auto pistols with reloads in my opinion is leaving too much expansion of the case mouth after seating and crimping. Most all of the so called straight walled semi auto pistol cases are slightly tapered to facilitate chambering. if you leave the case mouth larger than the remainder of the case you can expect trouble with your loads. The taper crimp die if adjusted properly both provides the needed crimp and also eliminates that expanded case mouth. The Lee FCD just does it easier in my experience. Unlike bottle neck cases, you really have to mal-adjust a crimp die to bulge a non bottle neck pistol case.

 

[bgswans]

Are you loading a bullet with a cannelure?

 

[Blitzfike]

Are you loading a bullet with a cannelure?

With the Lee Factory Crimp die you don't have to have a cannelure. It will compress the case mouth into the bullet making a secure crimp with or without a cannelure. I make my own 223 bullets using 22 rimfire cases to make the jackets. I do have a cannelure tool, but find that it is not necessary to make a cannelure on the bullets when using the Lee FCD. A major irritation for me is haveing a bullet set back into the case on feeding in an AR or other semi auto rifle. Stopping to clean out the loose powder that got into the action was what made me crimp all my semi auto rifle loads. For single shot or bolt action, I don't necessarily crimp them.

 

[bgswans]

I am currently loading 25 gr of Win 748 with a 55gr Hornady bullet with cannelure but not crimping. I have run several hundred rounds thru my M&P 15 without issue so far. I understand the reason some choose to crimp, but to avoid the extra effort of making sure all my brass is exactly the same length for proper crimping I choose to just make sure my cases are under the max length and cartridge OAL is correct.