I'm struggling with accuracy with my ar it's a 6x6.8 BHW barrel.

Z

zr600

New member
I'm struggling to get good groups with my ar it's a black hole weaponary barrel 6x6.8 shooting 87 g hornady hpbt. It used to shoot .5" at 100 and right at 1" at 200. Now it's 1.5 at 100 and anywhere from 1.5-2.5 inches at 200 I haven't changed anything same load brass except I put on a new handguard and barrel nut could this have anything to do with it?
 
Originally Posted By: zr600I'm struggling to get good groups with my ar it's a black hole weaponary barrel 6x6.8 shooting 87 g hornady hpbt. It used to shoot .5" at 100 and right at 1" at 200. Now it's 1.5 at 100 and anywhere from 1.5-2.5 inches at 200 I haven't changed anything same load brass except I put on a new handguard and barrel nut could this have anything to do with it?

It could be a change in harmonics due to variation in torque. By any chance is the gas block inside the hand guard? How many rounds down the throat? Same brass HS?

Greg

 
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Same brass the gas block is under the handguard. Throat should be good only like maybe 300 rounds down the tube.
 
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Originally Posted By: zr600Same brass the gas block is under the handguard. Throat should be good only like maybe 300 rounds down the tube.

Check the clearance on the block and guard. I've seen this when things are very close and they end up touching during firing.

Greg
 
Ok it has very little to no clearance on the top so I'm guessing this is my accuracy issue. Out of a four shot group I had two touching then the other two just randomly in different places ways away from the two touching that this load shot good before. So hopefully a new gas block works. What's everyone recomend for a new gas block in this situation I need an adjustable one too.
 
Originally Posted By: zr600Let me guess that's why Ritches and all your ars don't have the handguard over the gas block?

Actually we run quite a few covered GB's. Any of mine that are covered and vented are adjustable from the side through the slots.

Greg
 
Originally Posted By: zr600Ok it has very little to no clearance on the top so I'm guessing this is my accuracy issue. Out of a four shot group I had two touching then the other two just randomly in different places ways away from the two touching that this load shot good before. So hopefully a new gas block works. What's everyone recomend for a new gas block in this situation I need an adjustable one too.

The BTE micro works well for us. If those aren't available the one from JoeBob will do the job.

Greg
 
Ive run low profile GB under all my AR15 6x6.8 builds with 15" guards. Never an issue with them touching or binding up to them.
 
How much clearance do I need? There might be a little it's just hard to tell I can tell there is room on the bottom of it but it's really tight or touching on top. Also the bte micro wouldn't work for me because I have a bull barrel which I need a .936" gas block right?
 
I also have a .936 gas block on my rifle. Its JP low profile .936 with a OD of 1.38.. My hand guard is a Samson evolution and has an ID of 1.58.. I have about 1/4 inch clearance on top and a little more on the bottom.. It seems like enough clearance from how it groups well..
 
If nothing changes pull your HG & bbl nut & reseat. May just have something behind the nut and shoulder on barrel?...just a though.
 
Ok I measured my gas block today and it's 1.65 tall and the hand guard is 1.785 and it's hitting on the top of the gas block. Could I just grind down the top some or what should I get? I want an adjustable one because I'm going to be running surpressed and that would be highly recomended for a surpressor not?
 
Originally Posted By: zr600..Could I just grind down the (GB) top some...
That would be my next step, but convince yourself that the amount of material taken off won't effect the integrity of the GB. Also a good time to re-seat the barrel into the receiver, if not already done, as others have mentioned.
 
Before you get too involved with grinding down the gas block, and since the barrel has been removed during the interim, my guess would be that you may not have the barrel/nut seated in the exact same spot with the same torque specs as originally put together...That little difference can affect the barrel harmonics, which will change the accuracy factor..
 
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