Remington 58 won't feed from the mag

[10X]

I've run into another problem with a friend's shotgun. When pulling the operating handle back to chamber a shell from the mag tube the bolt just locks back. It does not release to chamber the shell.
The shell contacts the carrier latch, but does not push it back to release the bolt.

I've cleaned the gun thoroughly, the carrier latch moves freely, I put in a heavier mag spring, the shell pops freely from the mag tube. It just doesn't push the carrier latch to release the bolt.

If i push it with the shell on the carrier, the shell chambers.
The latch doesn't appear to be worn, it is bent as shown on schematics, the dog appears ok as well.

Any other thoughts on what I might do? I need some ideas.

 

[Kp321]

Does the shell feed properly when fired? The shell coming out of the mag tube doesn’t always have enough force to trip the feed latch when hand cycling. If it doesn’t trip the feed latch when fired, look for a burr or bent place on the carrier tongue where the feed latch latches. If this tongue is worn, the feed latch can seat too deeply and be hard to trip.

 

[10X]

Tried a shim on the carrier latch to reduce the travel needed to release the action. Didn't make a difference. I cannot get an understandable answer from my friend that owns the gun. I will go out and shoot it when the weather is better.