quick question keyhole problem

[gumpokc]

skeet,
it is .22 special, rather old pump action rifle of my grandad's.
the ammo being used is called .22WRF
they only make a production run of it once every 3 years, as part of their "obsolete" ammo production.

it doesn't od it every shot, on slow fire she's a sweet little number, but speed it up abit, and she seems to start keyholing.

checked the bore, it looks decent, patches weren't too bad, but i may try to let her soak and see if it is leading. Just seems iif it was leading, it would be all the time, not intermittant.