Joshb has it right! The closer to the butt the better. ............ Adding weight to the mag well or (worse yet) the fore-end may cause your rifle to be sensitive to throwing shots either right or left randomly as the rifle recoils if your shoulder isn't perfectly square to the rifle on a consistent basis. .............. You'll be better off to drill into the butt with a spade bit and pour in shot then replace the butt pad. Speaking from experience hereGet yourself one of those "strap on " cheek rest/shell holders. Slice it open and fill that with lead shot. Sew it back together. Voila!
