Re: Can't lower my S.D. HELP!!!
Have you annealed the necks? Work hardened necks will cause real bad ES / SD. Also, as stated, try non magnum primers. Win LR primers are actually real good with H1000, Wolf LR, and Fed 210m are also real good options. Magnum primers *USUALLY* only come into their own when you head north of 90 grains of powder, and/or are using slow ball powders. Also, if you shoot extreme cold weather -20 F. or below, then using a Mag primer can make a difference. I find the Win LR primers to be a good balance of Almost as hot as a Mag primer, but still "mild" enough to give good chrono numbers once you have your other things like Neck Anneal, Seating Depth, Brass Prep done.