wolfie Posted November 18, 2009 Share Posted November 18, 2009 Someone help me out. I forgot what the formula is for how much your POI changes at 25 yards for every 1 1000ths of an inch in front sight elevation. Trying to get the right front sight for my rear fixed Heinie on a Glock 34. Heinie web page says that G34 often shoot 2.5 to 3" high at 25 yrds and offer a higher front sight should this happen. Link to comment Share on other sites More sharing options...
bulamike Posted November 24, 2009 Share Posted November 24, 2009 ooh not sure of the formula, but I went through one hell of a time trying to work adjustable sights on my G34, enough to where I sold it out of frustration. I recall having to go to a .215 tall sight mated with my adjustable rear, the best setup I had were the sevigny combo, fixed sights, still had a fiber optic front .215 and rear Warren Tactical Rear. Link to comment Share on other sites More sharing options...
kevin c Posted November 24, 2009 Share Posted November 24, 2009 I do believe the formula is: Change in POI equals change in FS height times the distance from the rear sight to the target divided by the distance from the rear sight to the front sight (all units of distance being the same for each measurement - inches, feet, meters or whatever). Link to comment Share on other sites More sharing options...
Va_Gunner Posted November 25, 2009 Share Posted November 25, 2009 I just took my Spartan to Dave Dawson and he is hooking me up for the same issue. I'll let you know where i end up. Link to comment Share on other sites More sharing options...
Flexmoney Posted November 25, 2009 Share Posted November 25, 2009 There is a thread with the proper formula in the FAQ's on the 1911forum Or, you can do a search here. I've probably posted it a half dozen times in the past. Link to comment Share on other sites More sharing options...
Guy Neill Posted November 25, 2009 Share Posted November 25, 2009 Here's an excerpt from a piece I wrote a while back that may help. Values from the formula I derived match the values listed in the table on Brownell's website. δF/SR = y/(SR+R) with δF = change in front sight height SR = sight radius y = distance between aiming point and impact point R = range or δF = (SR ● y) / (SR + R) all values are in inches (● signifies multiplication) For our example, y = 3” SR = 7” R = 25 yards = 900 inches δF = (7 ● 3) / (7+900) = 21 / 907 = 0.023” (actual number is 0.02315”) Guy Link to comment Share on other sites More sharing options...
Xfactor Posted November 30, 2009 Share Posted November 30, 2009 I worked out a formula a while back and posted it with some simple instructions over at M&P Forum a while back... here's the link I subsequently found out that this is the same formula the AMU uses, so it works. Link to comment Share on other sites More sharing options...
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