Since I am the guy who has held the gun in really good light, with a magnifying glass, you need to trust me that it does not have a liner. I understand how you might come to that conclusion based on the photo I posted of the muzzle, but it is misleading. The serial number dates it to 2013, and I believe they had shifted to threaded barrels rather than V-block by then. I think it is a stock gun with an incorrectly bored barrel. The shaft of a drill bit of 0.155" will fit in the muzzle, while one that is 0.162" does not.
I bought a box of 17M2 ammo, and it chambers just fine.
I called Ruger customer service and they have sent me a return authorization.
Stay tuned.
