Will eat your sks piston! - NcSTAR SKS Gas Tube Scope Mount MSKS

Doesn't fit my Yugo 59/66. There was a large amount of forward/backward movement. The craftsmanship is also very poor. The top rail is held onto the tube using four screws. The screws are not held with loctite or any adhesive and the holes drilled in produced jagged metal inside the gas tube. This metal impeded the insertion of the piston into the tube and scratched it. I wouldn't trust this set-up to function reliably.

The top rail isn't very secure either but can be removed easily and if it were quality, would look very unique on an sks.