On the rifle pictured (Converted Mod 70) as maybe by Bob Smith, I think
From te looks of it, as I have had them, using a screw for the bolt stop/release, it's a Bob West job.
I still have one, but had Duane Wiebe make a conventional type Mod 70 bolt stop. Also have a Tom Burgess altered one and a Duane Wiebve altered one with a total different bolt release. Nice, but it removes and peep sight option. Probably could go to the other side and fit a Mauser unit.
