Ruger 10/22 rear cleaning hole. This allows the barrel to be cleaned from the breach eliminating damage to the crown.
The receiver is mounted on a special mandrel and drilled on a lathe.
The hole is in perfect alignment with the bore.
Jeweling (1911 barrel hoods, Ruger 10/22 bolts, rifle bolts, anything else you can think of)
Oversize Ruger 10/22 trigger pin installation. The larger pins eliminate the loose fit between the receiver and trigger guard.
Requires modification of the trigger pin holes.