This Ruger manufactured early variation piston block plug is for the early model 44 semi-auto carbine and lacks the threaded hole for the piston plug set screw. This early variation piston block plug is in very good condition with light wear. (file photo)

Note: Ruger model 44 semi-auto carbines with the following serial numbers have been observed with this early variation piston block plug:

No Prefix: 61450, 64382 & 95121