How Far to Drift Rear Sight?

[kbm6893]

I've been shooting a long time so I don't believe it's shooter error. My shots hit about 3.5 inches to the left with my SR9C. How much do I need to drift the rear
Sight? I've never had to adjust a sight before.

 

[GunnyGene]

I've been shooting a long time so I don't believe it's shooter error. My shots hit about 3.5 inches to the left with my SR9C. How much do I need to drift the rear
Sight? I've never had to adjust a sight before.

First, do you have a solid bench rest? If you don't, then don't mess with it. Next, at what distance are you shooting? It's all about the angles. 3rd, do you have an adjustment tool or do you plan on using a punch and hammer? You can do it with a punch, but it's not recommended, since you can easily make the problem worse in the other direction or damage the slide or sight. Be gentle. I'd advise scribing a very fine line alongside the sight in the dovetail before you do anything, so you have a baseline to judge movement from.

As for how far to move the sight - not much. Move it only a tiny fraction (less than the thickness of a fine hair) at a time, take 3 shots, move it some more if needed, take 3 more shots, etc.

 

[s4s4u]

My shots hit about 3.5 inches to the left with my SR9C. How much do I need to drift the rear Sight?

How much you would have to drift the rear sight is relative to the distance you are shooting.

 

[kbm6893]

It's about 15 yards away. I can bench it but then I'll be shooting from 25 yards to the target.

 

[blume357]

I'm no expert... but I might give it about a 16th of an inch and see... then again you might want to move your right leg back a tad and see what happens... I was in a class with a friend shooting my Sig p226 and he suggest I do that because I was shooting to the left a bit... but then we were shooting at over a hundred yards.... (Sig Academy: Pistol Distance Shooting Class)

 

[22/45 Fan]

The calculation you need requires knowing the sight radius (in inches) the distance to the target (in inches) and the POI error (in inches).

For example if you are shooting at 25 yards (900 inches), the gun's sight radius is 5.5" (as it is on my SR9C) and you want to move the POI 3.5" to the left, you need to drift the sights:

(sight radius x POI error)/ shooting distance = (5.5"x3.5")/900" = 0.02" to the left for the rear sight or to the right for the front sight.

Substitute your data if the numbers are different from the above.

 

[charlesappel]

The calculation you need requires knowing the sight radius (in inches) the distance to the target (in inches) and the POI error (in inches).

For example if you are shooting at 25 yards (900 inches), the gun's sight radius is 5.5" (as it is on my SR9C) and you want to move the POI 3.5" to the left, you need to drift the sights:

(sight radius x POI error)/ shooting distance = (5.5"x3.5")/900" = 0.02" to the left for the rear sight or to the right for the front sight.

Substitute your data if the numbers are different from the above.

Thanks for posting this. Very useful information.

 

[blume357]

I thought I posted after 22/45's post with the calculation for your specific problem and I think it worked out to .031" or about half of what I suggested... by his numbers my 1/16th of an inch would have put you just about 3.5" to the right which probably would have worked out because you then could have figure out to knock the rear sight half way back the other way.

 

[gb6491]

FWIW: Brownells has a sight correction calculator page that you just plug the numbers into: http://www.brownells.com/GunTech/Sight_Correction_Calculator/detail.htm?lid=13093

Regards,
Greg