I've owned this rifle for a few months and somehow never looked down the bore from the muzzle end. The rifling is so shallow that it's invisible looking from the muzzle unless a light is shining down the barrel from the breech. It looks like a tiny shotgun bore.

The rest of the gun looks like it had very little use considering it was made in 1957. It a commercial model.

Did these barrels come this way or has mine been shot out or lapped out?

Up until a couple weeks ago it shot great. I'm chasing an accuracy problem that is most likely me, but it caused me to look down the bore finally.