My 223AR only likes one bullet?

[Viperdoc]

I have been trying to find some accurate combinations of bullets and powders for my 223 AR with a Krieger 7.7 twist barrel. Hope to use this for dual purpose as a varmint rifle but also possibly to try and compete as a match rifle (200 yds at our home range).

Have tried Hornady VMax, Berger 64 for the varmint bullets, and Sierra 69 and 77 MK for the target bullets. So far, the only consistent load that shoots around .5 is the 77 with Varget or AA2520.

The rest all shoot over an inch, having tried TAC, H335 for the lighter bullets, and AA2520 and Varget for the 69's and 77's. I have tried neck turning, adjusting neck tension, etc as well, but did not appear to make much difference.

Really would like to get a good varmint load that works as well or better than the 77's.

Is it possible that this fast twist will only shoot the 77's well, or am I missing some other combination?

 

[7x57]

All of my uppers (20" NM set up for OTC) shoot fine with RL15 or Varget, but my last barrel (Kreiger 1:7.7 from CLE) would not shoot that well with those powders and smk77. I found that it really likes H4895, which I had not used before. I don't fuss with seating depth or neck tension for the "short line" ammo, and don't think it really matters that much.