What does everyone think about the Nosler J4,Custom Competition,J4 Comp,whatever they're calling them now) .224"/52gr projectiles? How do they compare to Sierra MK's? The only rifle I've used the J4's in really liked them.It was a Savage 10FP/308 and grouped almost .100" better than MK's,both in 168gr.I talked a buddy of mine into trying them in his 300WM,but he said the MK's shot better in his.I guess I really want to know about the quality overall,any caliber/weight they offer.