I have had the same problem, but found that a small piece of black insulation tape provided enough protection to do the filling in situ.
I have had the same problem, but found that a small piece of black insulation tape provided enough protection to do the filling in situ.
AA S200 .177 (multi shot), Nikko Sterling Mountmaster 3-9x40AO
AA S400 .177, Nikko Sterling Mountmaster 4-12x50AO