Recently bolt started hanging up after firing to the point of having to sharply rap on bolt handle. Works fine without cartridges. Changed ammo brand, no improvement. Removed, disassembled and cleaned bolt. Didnt notice notice any scratches or wear areas. There has been no changes to the frame or scope additions. Ejection of cartridge is fine. Occurs with or without box magazine in. Cleaning improved first couple of round then hang-up returned. Thinking front bolt lug some how binding with shells additional space? Thx in advance for any suggestions or assistance.