I am using DPMS AR bull with 20in 1-9 twist barrel and .223 chamber.
Trigger is heavy, but can't decide what to upgrade with.
Federal Power Shok 50gr JHP have been amazing. I shot a deer at 100yards, and knocked it right out. 14x power helped place it perfectly. These are pretty stout at 3300fps or so.
Some hand loads are 3400fps at 50gr with 24in barrel in .223. I have hit over 3k with 69gr and 75gr bullets.
I use AA2230 for smaller bullets, R15 for most bullets 60gr and up. R15 load with 40gr requires some serious stuffing. AA has loads up to 68-69gr for AA2230 and I have load data for R15 down to 40gr. Varget works well, but I save that for other loads, it has been hard to come by. R15 and AA2230 are pretty easy to get a hold of. IMR 3031 and 4064 are more of a pain for plinkers/varminters for my .223 so I haven't tried them.
CCI and Federal primers.
There was a mud sale last year at the local range, so I picked up a hodge podge of bullets:
Sierra 40gr HP, 50gr HP 55 Blitz King, 60gr HP, 63 SMP Varminter, 69gr SMK.
Hornady 50gr V-Max.
Hornady 75gr BTHP.
Remington brass is saved for the 69gr SMK and 75gr Hornady. FC, LC, WCC and other brass for the plinkers/varmint.
2.24-2.25in is the longest I can go with the PMAG. I picked up a 20rnd PMAG this weekend from Brownell's. The rest are 30rnd. I wasn't getting much from stretching OAL and single feeding, so I just keep them under 2.25. 2.26 causes an occasional jam in the mag.
35gr and 40gr are almost as flat shooting as my dad's VLS .22-250 with 50gr V-Max, and still plenty for coyotes. One of these days, I can going to pop off some of his .22-250 with 35gr and stuff it full of 3031.