I primarily shoot 40 gr in my 223's and occasionally a few 50 gr. I have tried a couple of 1-8, three 1-10's, many 1-12 and 1-14. Pretty much true to the benchrest boys ideas the slower twists give the best groups. But with that being said I have managed to make them all shoot under 1/2 inch groups with the exception of the 1-8, using 40 and 50 gr bullets it always shot more to 3/4" groups.
Not a huge sample, certainly not scientific but since my 223's are used for paper and varmints, not deer, I will stay with 1-12 or 1-14. Never had a problem achieving excellent accuracy with them, the same cannot be said about my experience with the faster twists.
drover
