I sighted in my rem700 in 30 06 with my hand loads.First 3 shots thru same hole at 100 could not take pressure and shanked the 4th about .5" off!!
Certified, good group. Try to find more of that ammo in the same lot. #, your rifle seems to like that batch. It does vary, lot -to- lot. .270 is a fine caliber. Your AR seems to shoot on average, nothing to be concerned about. Yes, you can tighten up the groups, all depends on what you want it to do. You can always switch out uppers to a varmint style if you need to go sub-MOA. Extra uppers are never a bad thing, IMHO.
Accuwedge and then better ammo may improve your accuracy. If not then consider another upper. I'll let you know about the accuracy with the PSA upper hopefully in about 2 weeks. I've got some more loads worked up to try and see how it does with them.