I have never had a failure to get the sight square with the rear blade using this method. most of us need an A or B sight, 'C' on down seem to shoot to high for most folks. I see a lot of rifles with a 'C', which is the middle height. At this point, the insert should be tightly in place in the slot, but extending above the radius of the sight plane. Make certain it is pushed all the way in and is flush with each side of the blade for its proper seating. When you have cut right across the front sight blade adjacent to its rear face, stop! You can use a thicker shim - like 1/8' thick brass to make sure that the top of the front sight slopes away from the face you look at. for the 03A3 they offered different height blades. Using the parallel action pliers, carefully squeeze the slightly over-size insert into the sight blades slot. Before you file too much, it would be good to fire at different distances. Now, filing the front sight raises the impact of the bullet. An ideal situation would be to fire your new muzzleloader and find it hits low on the target. Lowering the front raises the impact point. Instead use the rear sight as the pivot point and push the file sideways back and forth across the front blade. Raising a front sight lowers where the bullet will hit. Do not try to push the file backwards and forwards in the conventional way. Press the file firmly onto the rearsight with the thumb of one hand. This may be useful in determining how much. 44 Black Powder Revolver for MLAIC competition. Move or adjust front sight in opposite direction you want bullet impact to go. 'File Work' - Adjusting Front Sight of a Pietta 1858 Remington. Then, as suggested earlier, rest the back of the file on the rear sight with a shim to protect the rear sight. Move or adjust rear sight in the direction you want bullet impact to go. Rought the sight down filing in the normal way. That is a bastard of a file to use for a fine cut on sights.

I'm no expert, and I proved that by filing the front sight of my CZ-85 crooked, but I think it's this bastard :

How to file down front blade sight