i was wong

i bought a BCA upper in 6.5 Grendel .picked up a box of hornady Black 123 sst . i load my own, all the loading components had not yet arrived. the black shot horribly . after working up a few different loadings and installing a EC tuner brake and adjusting it to the better loadings . i then used the Black stuff to foul the barrel after cleaning . then 3 went through one hole@100 yd .not that I'm pissed