If you mill the 41 slide to same profile as a 46 radius cut 46 slide it will not fit your 46 square cut barrel. You will also need to mill a radius into your 46 barrel. If you are milling the barrel you may as well mill it to take the 41 slide as it is.I will mill the 41 slide to match later issue 46 slides with a radius in that corner (instead of square) to eliminate the stress concentration. The later slides were much more robust.