Brownells Gunsmith Tech Corner - March 2005
By Mark Hudson
Question: I have a 77/22 Ruger Mag bolt-action rifle. I’m having trouble
with extraction of fired shells. I have miked the fired shells and
they are .0005 bigger in size as compared to an unfired cartridge.
Is there anything I can do to solve this problem without replacing
the barrel? If not, could you help me understand what causes this
to happen to the barrel?
Answer: You may have a rough chamber, a damaged chamber at the
extractor cut, or the firing pin may have impinged on the breech of
the barrel, raising a burr. You may also have a bad extractor. The
minimum cartridge diameter of unfired brass on the .22 Mag. is
.238", and the maximum chamber diameter is .245". From what
you stated, you are well within specs on case expansion.
Question: I’m looking for a scope mount for a standard Mini-14 that
doesn’t mount on the side. I was wondering if your
No-Drill, No-Tap Mount System would fit a
Mini-14 series 186. Also, could you tell me which mounts would fit
this model?
Answer:That mount will fit your Mini 14. It attaches to the rear
sight-mounting flange on the receiver, so it will require removal of
the rear sight. This mount will accept any Weaver-style ring.