have just purchased a rockckuckker for 223 and 308
started with the 223 and have some questions
when trying to set up crimp die I am having problems with case distortion it seems that either the bullet is to loose or the case distorts I assume it is something I am doing but is it possible the die is not correct ?

Mickey
Welcome.
Just like firearms, inaccuracy is seldom the weapons fault.
Are you loading for a semi auto? If not, you don't need to crimp.
Back the crimp die out and slowly, turning it down one RCH at a time until you feel engagment. Then turn down one more RCH.
You may need to turn the case necks to a uniform length.
Jim

Or better yet...use Lee Factory Crimp Dies for crimping.

Thank you for the reply
yes this is for an ar semi auto
maybe my procedure is incorrect I have been trying to get it set without primer or powder I backed off the height pin and manually set the oal brought the ram all the way up screwed die till it touched went in 1 rch at a time until I felt very slight resistance bullet was still loose went 1 Bch and shoulder collapsed very slightly bullet was snug but I feel not tight enough for an ar semi auto am I missing something?

Back off the seater die and skip the crimp.

It is not needed in the AR

if the crimp is not needed how can you have an accurate round if the bullet is in a different position when the bolt slams shut all the factory ammo I have checked the bullet is tight enough that it wont move ,when I cycled the round through the gun at the point just before the shoulder collapsed then pulled the bullet back out it had moved .025

quote:

Back off the seater die and skip the crimp

A crimp is not needed for the 223 or 308.

obviously I am making a mistake somewhere else i am going to go back thru everything and try to find out where I have gotten off track the way it is now will not work thank you all for your time

You are crimping too much; back off the seater die until it does not crimp at all, then screw the bullet seater down to where you want it. No need to crimp anyway for ARs. But if you want it, carefully screw down the seater die whilst backing off the seater screw an equal amount. A little goes a long way here and the reason you are buckling your cases is that you are trying to crimp way too much, which is a bad thing. That makes the bullets loose. If the bullet is loose with no crimp then you need a smaller expander ball.

thank you for the responses the expander ball in the seizer die measures .2265 so I am going to polish down to .2235 and see how that works out, again thanks for your time

If you intend to shoot the AR in competition you are better served not crimping your bullets. Sufficient neck tension from sizing is all you need. Crimping swages the soft lead core of bullets, moving the center of gravity from the axis of rotation. This is a source of inaccuracy. This inaccuracy becomes more pronounced with distance, which is a very good reason why no one with a NRA classification above Marksman crimps their bullets.

Remember

If you are going to crimp with your seater die

All your brass will need to be trimmed and a length maintained to work correctly

Friends don't let friends crimp ammo for their ARs.

got it no crimp ,the problem was with the sizer ball was to big polished it and all is well thanks

Just to add, I never crimp for my AR15 or M1 Garands (30-06). Just set up for full length sizing and you'll be good to go. Don't bother fine tuning the loads OAL - size to the recommended max magazine length - unless you're going single shot and want to customize to the throat length.

I have been trimming case to -.010 of the max case length is that not correct,i got off to a bad start with the os sizer ball and reevaluating everything have spent the last 4 days reading everything I can but at this point there are many things I am not to sure of so I hope ya'll don't mind some stupid questions