??????

[William Suter]

I was having a little issue getting a good cheek weld on one of my AR's so I added a 1/2" riser. I know its gonna shoot lower but how much? Rifle is a 6 ARC zero'ed at 100yds. Google says it will be lower by the amount I raised it. I don't believe everything Google tells me. FYI, the riser made a world of difference and is now comfortable to shoulder.

 

[hm1996]

First of all, it will not be lower; just the opposite. The bullet strike will move in the same direction as you move the rear sight. Secondly, it will be a lot more than the same amount you move the rear sight. Assuming .5" movement of sight, 24" sight radius and range of 100 yards = 75"

That formula checks out pretty close to data on my match rifle. Rear sight 1/4 moa click = .0015" but my barrel was 26+" so sight radius woould be over 30". .5" would be about 333 clicks and translates to 83".
Go shoot it to be sure.

 

[William Suter]

The rifle is scoped. If you raise the scope the bullet impact should be lower shouldn't it? I understand if I was using sights but I'm not.

 

[hm1996]

That do make a difference. Yep, it should shoot lower. Your line of sight should be 1/2" higher than it was but will remain parrallel to the bore, just 1/2" higher.

 

[DAA]

I would just adjust my site height up by 1/2" in my favorite trajectory calculator. JBM is pretty darn good.

JBM - Calculations - Trajectory (Simplified)

jbmballistics.com

- DAA

 

[hm1996]

But that's cheating, Dave.

 

[William Suter]

I'm to old school. Head to the range with a bunch of ammo. I have found, (for me anyway), range time tells me everything I need to know. And I do like range time!!!!!

 

[spotstalkshoot]

Zeroed at 100 yards raising the scope will decrease the drop at 200 yards by about the same amount (1/2").
1.5 " above bore scope center 3.00 drop @200
2.0 above bore scope center 2.5" drop @ 200
Hornady ballistic data.

 

[Don_P]

....... I know its gonna shoot lower but how much? ...............

...... Head to the range with a bunch of ammo........

.....and there's your answer.

 

[William Suter]

.....and there's your answer.

That's the only real way to know for sure. I know the apps get you close and for some maybe spot on but for me, trigger time tells you the truth!

 

[IndexFinger]

LOL.... I go threw this same thing, but to the extreme side of raising your Scope line of sight over. I go back and forth on my main night rig with my day scope @ 2.5" above center of bore, with that scope set on 100 yrd. Zero . Then @ night mounting PVS-9 cantilever on-top of my day scope ring-set now moving a projected NV image 6.5" above Bore height . you can run ballistic programs, but Only way to make yourself 100% confident with your exact impacts is set-up paper at ranges and document real life.
.

 

[William Suter]

I shot the 6 ARC a few days ago. Kinda amazed.... POI didn't really change that much at all. It shot a little right of the bull but was really close to centered. Oh well, all it good.