I use .223 in my Remington 700 PPS, MR15 HB Target, Colt SP1, Colt Model 614, HK53a1, HK33A2, Colt M16a1, Olympic Arms M4 Carbine, and my Ruger KAC-556F (full auto Ruger). I didnt say I would snipe with the Ruger...(unless I was 50 yrds away), but my Remington consistantly puts shots in a 4"group at 700 yards. My AR15HB....oh 500 yards is an easy shot....I have a confirmed kill on a ground hog at 643 yards...not bad for a breeze in Pierre, SD.
NOTICE: Dear ATF I have Form 4 for all guns. (THEY ARE LEGAL)! Please don't kill me over paperwork or B.S.
I see you mentioned .308 in hk
I forgot to mention...my HK51B is for sale....its a short-barreled HK that has a HK21 belt fed tray on it...its a real fire breather...you can have it for $9,500 plus your $200 ATF tax...if you live in a class 3 friendly state.
I shoot with a guy who won the top civilian service rifle at Perry a few years ago(missed overall by one point) and he can't hold that with his 40-x in 7mm-08 at 600. (I have seen him go clean with 200-12X and consistently shoot 195s+ with a service rifle in bad conditions at 6.) It is considerably easier to dope the wind with a 7mm-08 or .308 than any load in a .223 (including the 80's which I doubt the Remington will even stabilize. I don't know the twist off the top of my head.) I know you might hold that for maybe a 3 shot group once in a while, but consistently 4"s????? That is some real shooting.