Rear Sight Height

[Mike in SC]

I have a Model 28 that was converted to .45 ACP. It currently has a .126 high rear sight blade and shoots approx 4-6 inches low @ 21 ft even with the sight almost fully elevated.

Should I go with a .146 or .160 high blade?

All replies appreciated

 

[old&slow]

Dawson Precision has instructions for figuring sight height that might be helpful.

http://www.dawsonprecision.com/images/Instructions/FrontSightHeight.pdf

 

[tomcatt51]

...currently has a .126 high rear sight blade and shoots approx 4-6 inches low @ 21 ft even with the sight almost fully elevated.

Should I go with a .146 or .160 high blade?

Neither. When you're "4-6 inches low @ 21 ft" you'd need a .196 rear blade. Yes, there is a .196.

SIGHT SLIDE, REAR, .196" | Brownells OOS but I think Midway also carries them.

 

[Mike in SC]

I am going to check out the Dawson sight calculation and see what comes up. Tomcatt, based on your input, I'm thinking .160. This allows for any pilot error.

Thanks

 

[cfplinker]

At 21 feet with a 4 inch sight radius you will need to raise the rear sight by .063 inches in order to raise the point of impact 4 inches. This means a .199 rear sight blade.

If you are getting a plain blade (no white outline) why not get the tallest and file it down to what you need even if you have to recut the notch.

 

[Mike in SC]

The Dawson calculation sez that for a four inch drop w/ my 5 7/8" sight radius I need a .156 higher sight. Going w/ a .160 blade from S&W. The taller blade from Brownells is out of stock, No B/O. That should get me there. Thanks again for the input.

 

[tomcatt51]

A .160 won't get you very close only raising your POI by 1.6". My math says a .196 would raise your POI right at 3" at 21 ft. Actually less if you run the rear sight back down into it's range of adjustment and definitely not 4-6" but all you're gonna get without shortening the front blade.

Midway shows the .196 as "no back order" you can BO at Brownells I tried it.

If you want a .196 PM me. I have a .196 with a standard notch and one with the notch widened to .140" (+ .015") and knife edged. Much better sight picture on a 4" gun with a .125" wide front sight.

 

[spdguns]

As of last week, all S & W sight blades at Brownell's and Midway are out of stock. I called S & W and they are out of stock with an anticipated delivery of 6-8 weeks......