My gun should be about ready. I can't remember the rate of twist. I do want to shoot the heaviest, readily available bullet that I can find. I'm pretty certain it's a 1:7 or 1:8. The 62gr is what I see the most in JHP or SP. I see the HP is available as well... just never been a fan of the HP or ballistic tip while deer hunting with only one exception - Federal Match King -- Used to be $45 a box, but boy did it perform. Found out my .308 likes the Federal (blue box) Trophy exactly the same at about $20 a box. Back to the 5.56 ---- I'll have to look at the 62gr vs the 75gr when I get the gun back. Glad to hear the HP perform well though.