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Accuracy Issues with AR50...Need Some Help

 
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  #1  
Old 05-19-2013, 12:47 AM
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Join Date: Dec 2012
Posts: 3
Accuracy Issues with AR50...Need Some Help

Guys,

Took my AR50 out today for the first time. Unfortunately I'm having issue getting on paper (I'm talking can't hit a 4' x 4' plywood target at 200 yards....embarrassing but confusing enough that I'm looking for help ). Just want to get some thoughts on what I may be overlooking. Note that at the same distance on the same range I can shoot sub MOA with my Bushmaster AR15.

Rifle - Left Hand AR50
Scope - Nightforce NXS 5.5 x 22 x 56 w/ NPR-1 reticle
Mount / Rings - Nightforce Unimoumt
Rounds - 750 grain Hornady AMAX factory loads
Distance - 200 yards
Range Slope ~ 6 degrees down hill measure with Nightforce ADI
Wind - Minimal....less than 5 mph crosswind

General Comments
Rifle was new in box. Swabbed barrel and chamber and lightly oiled both prior to shooting.
Bench is a custom 4' x 6' bench I built specifically to handle this gun.
Rest is a Rock River Jr under the forearm and bean bag in back. No movement even when not shouldering rifle.
When mounting the scope I used bubble levels immediately in front of scope base to level rifle longitudinally and transversely. I then mounted scope and leveled with bubble level on elevation adjustment knob initially followed by fine tuning using a plum bob at ~ 25 yards. After verifying all levels I torqued the Unimout and ring screws per Nightforce.
Prior to shooting I bore sighted with laser at 50 yards (max distance I could see laser) to 2 inches high (~theoretical bullet rise I per Hornady). I then backed up and fired x2 shots shots at 200 yards (both clean misses). At that point it was dark enough to see bore sight laser at 200. I had to adjust two clicks down and 1 left (theoretical 0" bullet drop / rise per Hornady....ie "dead on"). I then fired two more shots and neither cut the plywood.
I figured I was flinching as I have never had trouble sighting in. I've got the same exact scope except its 3.5 x 15 x 50 on my AR15 and I can shoot sub MOA from the same exact spot. At that point I had my buddy film me on the 3rd and 4th shots and on both I appear stock still. For y'all's info the recoil is comparable to my 30-06 but the shock wave is quite significant which I anticipated. In other words maybe I got the usual "wiggles" but nothing significant.
Thought on the issues.....?
The only thing I can see is possibly parallax issues. I'm no expert on correctly setting this but I followed Nightforce directions and I can't see it effecting the bullet flight that much. Y'all's thoughts?
Anything else I might have overlooked? Is the 6 degree down slope significant enough to have this effect. Haven't worked ballistics yet but I can't see it being the culprit.
Thanks,
Josh
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  #2  
Old 05-19-2013, 01:51 AM
Silver Member
 
Join Date: Mar 2010
Location: Portland Oregon
Posts: 123
Re: Accuracy Issues with AR50...Need Some Help

I always start off at 25 yards when I sight a rifle in just for this reason. I get the windage dead on and elevation close then move to 100, and so on. Just the way I do it.
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  #3  
Old 05-19-2013, 06:30 AM
Platinum Member
 
Join Date: Jul 2004
Location: Texas
Posts: 5,441
Re: Accuracy Issues with AR50...Need Some Help

To save time and money I always bore site the barrel on a round target at 100 yards. (Look down the barrel with the bolt removed).

With the barrel bore centered on the black dot, I carefully move the cross hairs to the center of the black bulls eye without moving the barrel.

After adjustments I re check the bore alignment with the target and look through the scope. If everything looks good I take a test shot. I can normally hit within 3 or 4 inches of dead center
the first shot using this method.

J E CUSTOM
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Old 05-19-2013, 06:57 AM
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Join Date: Apr 2012
Location: NW MT in a remote quiet area
Posts: 242
Re: Accuracy Issues with AR50...Need Some Help

Quote:
Originally Posted by J E Custom View Post
To save time and money I always bore site the barrel on a round target at 100 yards. (Look down the barrel with the bolt removed).

With the barrel bore centered on the black dot, I carefully move the cross hairs to the center of the black bulls eye without moving the barrel.

After adjustments I re check the bore alignment with the target and look through the scope. If everything looks good I take a test shot. I can normally hit within 3 or 4 inches of dead center
the first shot using this method.

J E CUSTOM

+!

and you can shoot into a dirt bank, if you still have problems and adjust from there. Spot where you hit and adjust.
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  #5  
Old 05-19-2013, 09:22 AM
Junior Member
 
Join Date: Dec 2012
Posts: 3
Re: Accuracy Issues with AR50...Need Some Help

Thanks guys. Guess Ill move back closer. Normally I start out at 100 and never had an issue getting on a 6" target. I figured with the 50 shooting "flat" out to 200 I could start there and save myself a few rounds (4 or 5 bucks a piece).
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  #6  
Old 05-20-2013, 08:17 PM
Platinum Member
 
Join Date: Jul 2004
Location: Texas
Posts: 5,441
Re: Accuracy Issues with AR50...Need Some Help

Quote:
Originally Posted by Raptor Shooter View Post
Thanks guys. Guess Ill move back closer. Normally I start out at 100 and never had an issue getting on a 6" target. I figured with the 50 shooting "flat" out to 200 I could start there and save myself a few rounds (4 or 5 bucks a piece).

Bolt action rifles are very easy to get on target at 100 yards by looking down the barrel at a
round black target. If you have ever shot aperture sights (Front and back) it is easy to line/
center the target in the barrel bore. and be very close to center. The rifle reaction to firing
will cause the POI to move slightly high and left normally, But you should be within Inches
of the middle.

I have an Barret M82 A1 and I sighted it in before it was assembled with just the upper
and the scope mounted. After placing it in a lead sled and strapping it down, I adjusted the
barrel until it was aligned with the target, Then adjusted the scope to the center of the black
bulls eye. Then I rechecked the barrel alignment and the scope.

After I assembled the rifle I fires a test shot and hit within 3 inches of center. After shooting
several rounds and verifying the zero I adjusted the scope and had a zeroed rifle in less than
5 shots.

I don't like zeroing any closer than 100 yards because the point of convergence is normally
less than 100 yards and can confuse some by trying to adjust to zero at the close distance.
By going to at least 100 yards convergence has normally happened and drop begins.

I also do the ARs this way with good results and very few rounds.

J E CUSTOM
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