Noticed this situation on the .22 and .30 cal. magazines for the AT44-10 and BT65 respectively. Tried different thickness o-rings available at the hardware store. Limited success. I'll try your approach but probably wit a rat-tail file not a power grinder. The chances of botching it aren't less but it'll be slowly. There's always the muzzle up and a knuckle rap on the forestock. Thanks for the idea.
