As others have said Large Rifle primers.
My OLD Ruger has a 1-14 twist and it shoots the Sierra 52 Gr HPBT Match, with 35.5 of N140 with a CCI 200 primers in Winchester brass into LESS than a 3/8 circle at 100 YDs.5 shot groups..
It also likes the Sierra 63 GR SMP's with 35.0 GR of IMR 4064, CCI 200 Primers in Winchester Brass. into Less than a 1/2 Circle and as small as 5/16 Circle 5 shot groups.
All depends on if I do my part.
I know you guys wont believe it without proof but that is your problem. 
--- H380 This also have produced some fine loads for me also.
DAB
