I do not own a centerfire bolt action but a friend has this problem. Browning A-Bolt in 7mm mag and 300Mag. Both doing the same thing. Bolts are sticking. He has tried Federal and Rem ammo in 150 gr bullets. Both A-bolts are stainless. He took the 7mm to a bench shooter who was suggested by a local gun shop to be a good gunsmith. He did a good cleaning on the gun and even test fired it with no problems. He went to the range Friday and both of his guns are doing the same thing. He sent his Federal ammo to company and they sent him some more ammo but there is nothing wrong with it I guess because it does it on Remington ammo also. I know sticking bolts are an indication of overpressure. He says there is more than normal discoloration around the head of the spent cartridge. I suggested that he do a very good chamber cleaning and inspection. He says he sees nothing like dents or scuffs on the brass. Anybody got any ideas or heard of this specific to magnums or Abolts or Brownings or something?