Home Forums Hunting & Shooting Rimfires A mystery Ruger

I bought a Ruger 77/22 at a local pawn shop that does an active business in firearms. It clearly has a factory barrel marked .22lr.





When I tried to shoot it, a round would not come close to chambering. A .22 long would go in further than a .22LR, and a .22 blank would fit in all of the way. Blackening the sides of the case would not reveal the problem.

Shown below is how far a .22lr round fits into the muzzle of this rifle.



This is how far a .22lr round fits into a different .22lr rifle.



It sure seems like this is a .17 diameter bore. Which is what my calipers roughly confirm.

Muzzle machining is not great, but does not indicate any modifications.


Neither does the breech--so it is not like someone put a liner in the barrel.


Is there any more reasonable explanation than this is simply a 17 HMR-2 barrel that was mismarked .22lr at the factory?