Can anyone tell me the difference (other than the obvious) between these two primers? I bought some plastic shells in 38 special and a large pistol primer is specified to load them (no powder). They are used for indoor shooting practice. I've got a lot of Large Rifle primers left over with no intention of ever using them (sold the large caliber rifles) and would like to use them up. I think they might be a little "hotter", but other than than that...???