If shooting 9mm major I have found a great bullet, a profile I was unaware existed until recently and it's Berry's (I'm not sponsored by them) 124gr hbfp thick plate. The hollow base does 2 things and that is 1, round nose loaded to same power factor compared to these berry's, the berry's hollow base shows no primer flattening at all, they are still round using same hs6 powder charge of 7.8/7.9 gr where the round nose shows medium pressure signs with quit a bit of flattening of primers. 2, hollow base makes better accurate due to the hollow base expanding a bit to virtually seal the barrel as the bullet travels through.