if sure mounts, scope, stock ect check out ok, check the crowning job , on my last new 527 is was poor, where the crown was broken from the rifling it looked like someone had done it by sticking a screwdriver in the barrel and giving it a couple of twists, after it was recrowned it went from 1,5" groups to shooting ragged one holers. on your ammo test did you clean and let the barrel cool between each make & weight its the only real way to gain a fair assessment for each round. ive seen guys on the range rapidly shoot a box of the cheap mil surp , then complain when the next 3 hornadys dont group well out of the hot fouled barrel especialy out of the lighter profiled barrels.