I have an old style RCBS seater for my .45-70. It uses the allen screw into a lead ball to tighten the lock ring on the die body. I've lost the instructions 30 years ago and haven't changed this die in ages. Can't seem to loosen the lock ring. I know the lead has flattenend, as designed, into the die threads. Seems like brute force was used in the past. Doesn't work now. Suggestions?