High scope mount on an AR

[Oldshooter]

Decided to put a scope on my AR with a handle top. I bought the leupold bar that fits into the carry handle. Put the scope on(its about 3- 3 1/2" above the bore) and sighted it in as follows; 3 inches low at 25 yards, and 2 inches high at 100. Now the little rifle groups really well (about 1 inch)( way better than I could do with the factory peep). Wondering what to expect at 150 and 200. Haven't been able to shoot that far yet. So can you fellas that are in the know give me a clue as to what to expect before I get to the range for a 200 yard sight in?

[rdmallory]

I expect it to be WAY High.

I have a high top .223 and put a 50mm scope on it and had to use the see through rings to get it to mount.
Took it prairie dog shooting this spring and found it dead on at 50yards and 14" high at 200 yards. Seams the bullet is still raising with the scope mounted so high.

Doug

[rickt300]

I traded a handle upper reciever for a flat top today to alleviate the problem. I shoot a lot at night and at close range, didn't want the guess work of holding over at 30-50 yards on feral hogs.

[Warhawk]

Assuming a 55 grain bullet, I was playing with the Hornady ballistics calculator and it looks like you have about a 285 yard zero. The chart below shows that you will be about 3.3 inches high at 200 and 1.1 inches low at 300.

Here is the chart.

 Input Variables
Firearm type   Rifle     
Sight Height   3.5
Bullet Weight (grains)   55
Ballistic Coefficient   .255
Muzzle Velocity (fps)   3240    
Temperature   59
Barometric Pressure (hg)   29.53    
Relative Humidity   78%
Zero Range (yards)   285    
Wind Speed (mph)   0


Ballistics Table in Yards
223 AR    55 gr., .255 B.C.   www.hornady.com
Range (yards)   Muzzle   50   100   200   300   400   500
Velocity (fps)   3240   3043   2855   2501   2174   1873   1601
Energy (ft.-lb.)   1282   1131   995   764   577   428   313
Trajectory (285 yd. zero)   -3.5   -0.3   2.0   3.3   -1.1   -12.8   -34.6
Come Up in MOA   -3.5   0.5   -1.9   -1.6   0.3   3.1   6.6

[Oldshooter]

Well I kinda figgered as much! After bore sighting I went out back and shot it a 25 yds, set it to be a wee bit low at 25 and shot it at 100.................Dont know where that bullet went but it didnt hit a 2 ft high piece of butcher paper with a 1 inch dot in the middle! So i lowered the 25 yard impact to 3 inches low and it hits about 2 inches high at 100. Dang I'm prolly gonna have to live with that for a while. The good news is it is prolly dead on at about 60-75. Now I'll have to set up a 200 yard spot to see for myself. But this gives me an idea how big of a "wallpaper" i'll need to catcha bullet!


Duhh!! Warhawk you posted while i was typing. Dont know why i didn't think of the ballistics calculator I've used it before. Thanks