quick question keyhole problem

[Cossack]

Keyholeing usually means that the bullet isn't stabilized. That the rifling twist does not match the length of the bullet used.
Gereally speaking the shorter the bullet the slower the twist. The longer the bullet
the faster the twist has to be. I suppose leading could cause it but that doesn't happen often to that extent in a 22. Are you using a light bullet, like one of the 30 gr high velocity loads? Seems like the smaller bearing surface on one of those coupled with a faster than normal twist rate in your gun could cause keyholeing. Try a standard velocity 40 gr bullet ... after a good barrel cleaning.