AR Sponsor
Posted: 9/5/2014 11:10:20 AM EDT
|
I have a new upper that is shooting 18" low at 100 yards. I have a scope that I use to test the accuracy potential of a new upper and I had to adjust it way up in order to get it on target.
I tested the same scope/mount on 3 other uppers and all were within a couple of inches of each other at the 100 yard mark. This new upper was way low. Accuracy is good and consistent. Upper is stainless, free floated with a standard A2 flash hider. The gas tube is normal and there seems to be no obvious misalignment. What might cause this? Could removing and reinstalling the barrel help? TIA ETA. PROBLEM SOLVED! Removed the barrel. Cleaned the mating surfaces. Reinstalled the barrel. Shoots where it should. Thanks for the help! |
|
Yes. No bridging and no binding.
I've tested a dozen or more AR's for accuracy using this scope/mount combo and even tough no 2 are exactly zeroed, they are always within a few inches of zero. ETA: Windage was within a couple of inches of where it should have been. |
| The upper's receiver face may not be square to the bore. This can be fixed by any gunsmith or you can return it to the factory under warranty. Try installing iron rear sight to make sure it's the gun and not caused by somebody messing with your scope. 18" low at 100 yards would make it close to impossible to zero with irons. |
|
Unless you built the upper yourself, best to get the supply/maufactor involved.
It does sound that the barrel is not mounted Center line with the upper receiver line, and the problem at hand. Granted that it could be as major as the upper receiver barrel socket not on face, or as minor as just some debris between the barrel extension front face to the barrel extension back face causing the barrel cant. So on that note, unless you have the tools and tallent to correct the problem (pull the barrel), then just have the upper factory warrantied instead. |
AR Sponsor