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What's keeping an 81.5 gr H20 case from equaling and not exceeding the velocity of a 74 gr H20 case? These are ADG numbers.Yes, it's the .220 FB. The barrel is a C6 CF barrel at 27". It's a tight chamber and cut to be .002" above new ADG brass. my CBTO is 2.360". I touch lands at 2.355". The bullet is in the lands at 0.005". New ADG Brass or resized brass with N570 67.8 grains gets me an average velocity of 2,968 fps average. I ran it up to 69.0 grains to 3,035 fps with pressure signs. The 67.8 grains gets me a vertical dispersion at 650 yards of 2" basically. But the 68.1 to 68.4 has the best disersion of half that, but it's very close to pressure and I'm shooting in Texas and the temps can kill ya. But that being said if I were only to use in the high country in the fall I would be at the 68.2 grains in the middle and I would shoot it all day long. At the 68.2 I was averaging 2,984 fps and an ES of 5. I confirmed it 4 times on 2 different days. It want's to be there. So that being said, I am going to cut a Brux Medium Palma at 26" and try to hit that node but I will be back at the 2,960 fps spot with the better dispersion.
To note: The only 7PRC barrel I cut was a 26" and I could not get to within 80 fps of what the SAUM pushed it.
Honestly I have no idea. I've only had one sample of the prc and only tried 195's. Same powder same primer same bullet same brass manufacturer. Could be the chambers, freebore, user, tongue out left side and not right. Well tight could be but the saum I was testing on like I said was tight and just above Adg brass.
