Keyholing / tumbling bullets

[Jeremiah10:23]

What causes keyholing?

I have a snub nose .22 I shot this weekend that shot perfectly at 20 yards but keyholed at 30 yards. This was the first time I had ever shot it.


What makes them do that? is it fixable or best to be disposed of. (H+R 930) (Yes this is the one that had the leading issue you guys helped me with.)

 

[rcmodel]

Leading was the most likely cause.
Followed by a damages muzzle crown.
Followed by funnel shaped muzzle rifling from cleaning rod wear.
Followed by the ammo itself.

Bullet weights that should stabilize would range from 29 grain Shorts to 40 grain LR.
Other odd stuff like the 60 grain Aguila will tumble.

First thing I would do is clean the barrel, forcing cone, & chambers real good with a bronze bore brush again and try a different brand of ammo.

rc

 

[lowercase]

I recently owned a .22 mag revolver that keyholed when I shot a certain type of ammo (CCI Maxi Mag 40 grain), but was fine with everything else.

 

[TonyT]

rcmodel has the solutions listed in the proper order.

 

[murf]

and the short barrel causing a low velocity (slower spin).

murf