Brass weight is an indicator of case capacity, but since brass has a specific density of about 8.5 1/2 grain case differece is only equicvalent to 0.06 grains difference in case capacity.
From the above data I'd suggest dropping the loads to get under 1025 fps and weigh each load carefully. When I'm trying for precision loads in small cases I weigh each charged to +/- 0.02 grains on a lab scale. It's a bit tedious but the results are worth it. Consider that subsonics are 1/3 the speed of typical bechnrest bulelts so they have 9 times the drop and vertical stringing for the same percent velocty variation. . Also subsonics have to deal with transonic stability issues. You have to use benchrest techniques loading subsonic ammo if you want to achieve the accuray at 100 yards of typical commerical supersoinic ammo, like a 223.
Bullet and brass weight isn't as criical as charge weight by a factor of at least five, but I sort brass and bullets to 0.1 grain. Better bullet manufacturers and some brass manufacturers have already done that.
Don't think that it's easy to get good accuracy in subsonics just because they're small and slow. It's just the opposite.
Last edited by LouBoyd; 05-28-2011 at 01:44 PM.
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