I use a 6.8 and 223 but never have really tested and hunted hard with the 300 blk. I have a 9" 300 blk aac MVP sbr. Where should I start besides the 110 black tip Barnes?
The barnes blacktip's or the new cavity back bullets if you reload. Also look at the makers Trex those three choices will be best for short barreled lower velocity performance.
I was impressed this past weekend with the new Hornady 190gr Sub-X factory ammo in my AAC 9" upper with a Ti-Rant 9mm silencer on it. Not as effective as the 6.8, but for subsonic, it worked well and was sub-MOA at 100 yards.
The 125gr ballistic tips work good too. The Barnes load is what everyone loves but for some reason we have kept most of them inside the 70-120 lb deer the kids have shot. They have been under the hide on broad side rib shots. Could be the case of ammo I got them. The ballistic tip puts 50 cent size exit on the deer and hogs they have shot.