Ken, thanks for the excellent information.
I found an online ballistics calculator at Beartooth Bullets:
www.beartoothbullets.com/rescources/calculators/balistics/I plugged in information from Head's Bunker about Kobra collimator sight zeroing (ballistic coefficient):
headsbunker.nothingbutguns.com/html/article_trajectory.htmlAnd information on the Federal (American Eagle) 124 gr. FMJ 7.62 x 39mm round:
www.federalcartridge.com/ammocat20.asp?s1=1I measured the height from the center of the SAR-1 bore to the top of the front sight post, which was 2".
Crunching the numbers revealed the following:
Range Velocity Energy Momentum Drop
(yards) (ft/sec) (ft-lbs) (lbs-sec) (inches)
0 2300.0 1444.7 1.26 -2.0
25 2232.0 1360.5 1.22 -0.0
50 2164.7 1279.7 1.18 1.6
75 2098.5 1202.6 1.15 2.7
100 2033.4 1129.2 1.11 3.3
120 1982.2 1073.1 1.08 3.4
125 1969.5 1059.4 1.08 3.3
150 1907.0 993.1 1.04 2.9
175 1845.7 930.4 1.01 1.8
200 1785.9 871.0 0.98 0.1
225 1727.4 815.0 0.94 -2.3
235 1704.5 793.4 0.93 -3.5
250 1670.5 762.1 0.91 -5.5
275 1614.9 712.3 0.88 -9.4
300 1560.9 665.4 0.85 -14.1
The way I interpret this is:
1) If you zero at 25 yards, you'll have a "far zero" of 200 yards;
2) The bullet will be no higher than 3.4" or lower than -3.5" anywhere from the muzzle to 235 yards.
3) I think this would be a decent battlesight zero, given the typical use of the AK-47 - "we ain't talkin' 'bout snipin' heah."
This 25-yard range has the advantage of being available at almost any shooting facility, even indoors.
Please feel free to point out if I am completely (or even partially) full of s**t, or if I am just reinventing the wheel.