Shoping list
Pair of tiny spot lamps and some red lens repair tape from a car shop. Go halves with a mate.
A yard or so of nice flexible twin core (mine if off a house table lamp and it has a switch in it)
A cheap scope mount.
A Panasonic LC-R123R4PG or similar. Got mine of fleabay, a pair for £14 delivered.
Work list
Cut the dovetail off the scope mount and drill and tap the large side for a suitable small bolt, mount the car spot lamp and fit the lot to your scope, add two layers of red lense tape to the spot lamp.
Attach the wire and switch to your gun so the switch falls w