Thanks BallisticianX for your easy understanding of this issue. Going to be running 38sc soon and was grappling with this issue . Have lots of Federal SPP. Several top GMs told me they use SRP and have increased FPS from 20-50. So I purchased a few packs of SRP of the top 4 brands to test, also fed spp, mostly regarding flattening, cratering etc. Next will come chrono. Will post results. Using 3n38, Pd 124gr JHP.