I've had similar experiences with a Model 11, but in .308 with 2 different factory barrels.

Looking at the bore with a bore scope showed large gouges in the rifling about 4 inches from the muzzle on one,

and chatter marks the length of the bore on the second.

Broke down and bought a Criterion varmint barrel and installed it this evening. This bore is smooth.

If you (or your gunsmith) has a bore scope, it will save you a lot of time, frustration, and components.