Author Topic: Adjusting fixed pistol sights (Read 1172 times)

lilabner · « **on:** March 25, 2004, 08:59:53 AM »

Is there a table or chart showing how far a rear sight needs to be drifted to make a two inch change at 25 yards? One of my pistols consistently groups 2 inches to the right of the aiming point. With that information, could a smith get me centered or is it a trial and error deal?

Mikey · « **Reply #1 on:** March 25, 2004, 09:45:03 AM »

lilabner: depending on the pistol you can probably do this yourself. With some pistols this will be by trial and error but with others there is a more scientific approach.

For example - if your pistol is a 1911, simply remove the firing pin (I forget if you have to remove the hammer to look down the firing pin hole) and center your 25 yd target in the hole, then see where your sights line up and correct the error. Same same as bore sighting a bolt action rifle with a scope, without all the bore sighters. HTH. Mikey.

KN · « **Reply #2 on:** March 25, 2004, 12:04:39 PM »

It is simply a mater of triginometry, figuring the angles and distance for offsetting the sights the correct amount. You have to realize that zero can only really be "set" for a specific distance with a specific load when you are all said and done. KN

gunnut69 · « **Reply #3 on:** March 25, 2004, 06:28:20 PM »

The simplist is to shoot the gun and move the sight. Deflection stays pretty close but can be affected by the shooters strength, recoil of a specific load etc. as will elevation, though usually to a greater extent than deflection. A screw operated sight pusher is a real benefit when sighting in (filing in) a set of 'fixed' sights..

lilabner · « **Reply #4 on:** March 26, 2004, 04:26:53 AM »

Near as I can tell, the sight is centered and was centered perfectly by the factory. The problem is, I "thumb" the pistol when I pull the trigger and that deflects shots to the right. I can't break the habit so have decided to live with it. I know they make a tool for drifting sights and the gunsmith could move it easily after loosening the set screw. The problem is I can't take the gunsmith to the range with me for adjustments!

gunnut69 · « **Reply #5 on:** March 26, 2004, 09:16:31 AM »

I assume there are witness marks present, if not scribe a mark on both the rear sight and the slide, exactly aligned with each other. Small and unobtrusive please. Take to the range with you the proper tool to loosen the retention screw(screw driver or allen wrench). I would advise loosening the screw at your shop in case resistance is met. It the sight is loose in it's dovetail almost no force may be needed to move it once the set screw is removed. A tiny hammer and a polished face punch is what I use to move those sights that still want a bit of convincing. Be certain the face of the punch is smooth. I use a white pencil available at sewing centers to mark the sights if a permanent mark is not desirable,. Move the sight in the desired direction a small amount. Remember, move the rear sight the direction you wish the bullet impact to move, the front sight moves in the direction opposite the direction the bullet impact must go. Caution as firing techniques may cause the pistols groups to move a bit. Depends on several factors. I usually shoot with my forearms supported on bags. Thumbing a 1911 can cause stoppages... Sounds weird but it is true.. I've never had the problem but understand habits!! The problem with calculating the amount to move the rear sight is measuring the sights movement. The amount needed for 2 inches will be tiny indeed and measuring that minute amount of movement is a pain. Besides, it is a bonafide reason to shoot some more.... If you should need one.
good luck!! Jerry