I'm a novice shooter and reloader. I am not getting great results in my 308 with RL-15. I was having weird issues with my 6.5 creedmoor using IMR4350. I decided to try RL-16 (Alliants temp insensitive powder) and it is working out very nice. Now again, I am not a good shot so my groups are nothing to write home about but my last test resulted in the following:
Virgin Brass:
38.6 gr: SD - 16.1 (7.9 if you exclude the first shot with reason given as cold/clean bore but this could just as easily be a reloading mistake)
39.0 gr: SD - 11.9
39.4 gr: SD - 13.1
39.8 gr: SD - 8.9
40.2 gr: SD - 7.6
40.6 gr: SD - 4.3
41.0 gr: SD - 9.1 (5 if you exclude one value larger than the rest, reason for this value unknown)
41.4 gr: SD - 5.7
41.8 gr: SD - 6.5
42.2 gr: SD - 6.0
Once Fired Brass:
38.6 gr: SD - 5.2
39.0 gr: SD - 5.8
39.4 gr: SD - 7.0
39.8 gr: SD - 5.7
40.2 gr: SD - 6.5
40.6 gr: SD - 6.1
41.0 gr: SD - 6.6
41.4 gr: SD - 4.8
41.8 gr: SD - 5.4 (If you exclude an outlier here of 2844 vs the next highest of 2829 you get an ES of 4 and an SD of 1.6, reason for this value[2844] unknown)
42.2 gr: SD - 6.7