I'll be sighting in at 25 yards on the "Z" Mark. After that I would like for the wheel marks to be accurate. Clicking to the 1 mark for 100 yards, 2 for 200, and so on. Since these are moa adjustments, I thought I might need the same sight radius as a rifle length gas system FSB for it to work out.
I just noticed this ^^^ The "z" mark is for 25 Meters (82.29 feet) The "z" was put on the A2 sights b/c when the army went from the M14 to the M16A1 the ranges were made at 25 meters to get a battle sight zero for the 1/12 twist M16A1 w/ the 55 grain bullet ( M193) When the M16A2 came out w/ the 1/7 twist barrel the proper distance would be 32 meters... So insted of changing all the ranges they added the "z" to zero at 25m, but when you go to the range, to shoot your pop up targets, you move it back down to 300. Allways use the small sight apature!!!
Distance in Meters M16A2/A4 bullet path true 300m zero
Meters Path inches
0 -2.5 ( this means the barrel is aginst the target, your sights are 2.5 inches above the bore)
25 ----- -0.33
50 ----- 1.56
100 ---- 4.37
125 ----- 5.27
150 ----- 5.8
175 ---- 5.94
200 ----- 5.68
225 ---- 4.98
250 ---- 3.82
275 ---- 2.17
300 ---- 0
Note that the bullet impacts .33 inches low at 25m This why it is necessary to raise the BDC to the "z" mark ( if you have older sights it might not have the "z" , so it would be 8/3 plus 1 click) Then return the sights to 8/3 for qualification or Battle
**** You do not have to do this for the M4 rifle just the A2/A4 rifle