RE: Question about barrel length in 7 mag.
Barrel length really doesn't have any effect on accuracy according to the custom barrel folks. Actually a shorter barrel should have less whip and thus have the potential for better accuracy. I've never tested the theory personally. As per rifle accuracy, that barrel might not like that bullet. Mt Browning Medallion does not like the 162 SST but shoots almost every other bullet sub-moa. If your handloading try Alliant RL-22 powder. It shoots well in most 7 mags I've seen.