I tried 121grs H-870,(180grs bullets) very too hot load,drop back to 116grs.H-1000 107grs(max),I tried 11grs a lot to hot.H-50bmg 120 grs(I tried 121grs(hot).I am using H-4831sc (102.5grs)150 grs bullet.Rcbs neck sizer dies,no good accuracy with it,may be the seater was not that good.I enlarged the muzle break by 1/64".I have mount problem with the .338RUM,the Leupold mounts,front base wont stay tight;the two rear bolts (base)dont stay where they should be...
