Have to savage 6.5 284 in savage one F-class the other 111 longrange hunter. Have older 65-284 win action post 70 1/9 twist. I get 1/2 to 5/8 groups at 3250 120 gr spt. In older mod 70 with 57 gr. old 3100 powder just stats to flatten primer on 90 degree days no problems with this gun. I wanted to shoot out too 600 yards so I bought the long range hunter with 26 in barrel hoping to reach 2950 to 3000 fps woth 140 vlds no deal at about 2850 to 2880 I show stiff bolt lift. and on a 15degree raise in temp leaves ejector mark. HSM with 140 vld 2850 good load. I have tried 4831sc 4350 rel17 hybrd 100 magpro and some real old bulk 4831. Some differences but still pressure issue.
This Gun reaches pressure about 2gr. before most powder data. also some vertical stinging. I shot one Norma factory round and it blew primer out and weakened my ejector. The neck is a little tighter than my f- class so in tried outside neck ream also I use comp redding bushing and seating dies. The back of this guns locking lugs also looks pitted and rough. Looking for Ideas on what the problem is. Am I expecting to much? I can get better vel with my older win model 70 with 24 inch barrel.