FL Sizing for AR-15

[Tex3030]

Recently got an AR that I am trying to load for. I have not yet sent a reloaded round down the tube. I have read that small base sizer dies are recommended for the autoloaders, and I have also read that FL dies are good for an autoloader. This has caused a little bit of confusion, so my thoughts are that I will start with the FL sizer and if I run into problems I will get a set of Small Base dies.

My question is about how deeply to run the the brass into a full length sizer for a gas gun. When setting up dies for a bolt gun I used a FL sizer that would just set the shoulder back a few thousandths. When doing this the shellholder did not come close to the base of the die. I tried following the directions that came with the Lee dies and do not understand them. The instructions read that the die should contact the shellholder at TDC, then be screwed in another 1/4 turn. This makes no sense to me because it seems that all this will do is cause more stress at the top of the stroke, but will not size the brass any more.

Is there a way of FL sizing the brass without using a mic gauge, previously I have done this based on bolt pressure and do not see how to accomplish this with the semiauto.

 

[coxhaus]

I think you will be OK as long as you full length resize the brass for an AR15. My buddy and I have shot over 400 hundred rounds each with no problems. He uses a FL RCBS die and I use a small base X die RCBS. I cannot tell any difference between his reloads and mine. I only bought the small base dies because I have a lot of military brass. I was afraid some was shot in a machine gun and might cause problems. I think the down side to small base dies is it may over work the brass which will shorten the life of the brass. Time will tell.

 

[Nitroman]

I think you will be OK as long as you full length resize the brass for an AR15. My buddy and I have shot over 400 hundred rounds each with no problems. He uses a FL RCBS die and I use a small base X die RCBS. I cannot tell any difference between his reloads and mine. I only bought the small base dies because I have a lot of military brass. I was afraid some was shot in a machine gun and might cause problems. I think the down side to small base dies is it may over work the brass which will shorten the life of the brass. Time will tell.

Bingo. Look on the barrel of your AR. If it is a Colt, it will have all the info you need as to twist, chrome/not chrome and chamber. Most, but not all, AR's have a 5.56 NATO chamber, which is just a little (I mean a little), different than a .223 Remington chamber. So like the previous poster, if you buy a bunch of once-fired military brass, it will need the FL die.

The Lee die directions are like most, the additional 1/4 turn at the top is just to make sure you really ARE bottoming out. Remember, the manufacturers are printing these directions for everyone. I believe if you are on this forum, you probably have a few more IQ points than the average Bubba-Hunter, don't worry about it.

Fire some rounds in your rifle and take a close look at them. I'll bet you can fire them a few times just neck sizing before you need to squish them back down with the FL die.

 

[Tex3030]

OK, thanks for the responses. The next part that has me concerned in loading this thing is that I am not sure what to look for when checking pressure on the gas tube. I have read that some people talk about how the gun begins kicking more and some have stated that this is a sign of high port pressure.

Right now my plan is to follow the guidelines set by Sierra with their AR loads. First round of shells is gonna be a 55gr SP or 64 Win PP pushed by H335. I never really thought about how much different it was going to be to load this compared to bolt guns. It almost feels like learning all over again.

 

[Loner]

Don't neck size ar brass. It can be done but is a major pita and if you stick one in the
chamber you are going to hammer the butt stock to get the bolt open. I've done it and
it isn't worth it. Anyone else who's done it will tell you the same. You want to bump the
shoulder about .002 to .003 thousands is all. So screwing the die down and caming the
press is not the way to go. Do some reading on how to set your die for a .002 bump.
Plenty of info on it out there. I strip my bolt, stick it back in the carrier and use a piece
of scotch tape on the back of the case. When the bolt will close that is as far as I go with
the die.

 

[coxhaus]

I think you will find reloading for AR15s is just as easy as bolt guns. The only difference is seating depth for heavy bullets are limited by magazine size. The Sierra AR loads are a good place to start. I have loaded both 55sp and 64 Win pp with H335 powder. It had great accuracy but the powder is a little dirty.