Good looking rifle.
The sprue can be easily removed with a pair of plyer's type wire stripper, with the little cut outs for difference diameter wire.
Using a moderate set of holes, pinch in 1/2 way, then twist/turn the bullet in the fingers. The sprue will cut off flush, or leave just a tiny pointed tit that can be touched with the flat side of the cutter's jaws, making it disappear.
I do this with my Tanner moulds that have no cut off.