Originally Posted by RT2506
Full length size EVERY CASE. Don't try to to load those MAX bolt action loads or you will beat your AR to death. I personally use a Lee Factory Crimp Die on all loads. The bullet does not need a crimp groove to use this die. Contrary to belief it does not destroy the accuracy of match bullets. Pay attention to the twist of your bore as to which bullets you can shoot. If it has a 9" twist like many do the 77 gr Hornady is about the heaviest bullet you can stabilize. Don't use FEDERAL primers. The ARs have a floating firing pin and can slam fire. Federal is the only primers I have had this problem with. Their cup is thin and sensitive.
Get all the magazines you ever think you will need NOW before the knee jerk reaction governmental bull hits the fan.
I don't use the lee die, but it can be useful at times. I roll crimp my fmj's but let neck tension hold the 75 grainers in place; you may have to use a lee crimp die in some rifles if they feed more roughly than mine. I fl size all rounds for my ar, use cci mil spec or small rifle mag primers only, and clean/trim a few hundred at a time after I mill the crimp out with a de-burring tool chucked into my drill. I use either 4895 or tac and either 55 grain fmj pills or 75 grain hpbt pills depending on what I want to do with it.
What chamber do you have??? If it says 5.56 nato, confirm that it is as some brands are stamped nato and are really 223. You could run into pressure issues using nato loads in a shorter throated 223 chamber. My dpms is a nato chambered 9" twist, so I'm pretty much home free until I pass 77 grain pills.