I recently bought a used 204 ruger barrel for my encore. Put a scope on and got ready for tack driving. At 25 yards bullets keyholed the target. Any suggestions would be appreciated.

Sounds like it needs to go back to T/C - they'll replace it for free.

Yes send it back. I had a 17 ackley bee that did the same thing.
send a target with it too. I think they chambered 20 cal blank for my 17 cal. Maybe they chambered a 22 blank for your 20 cal.?

Bill