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AR15 accuracy issues

So I'm going to hopefully get work on my 6 arc tonight and shoot it tomorrow. I'm going to make sure the gass tube is free floating, swap the scope and take the bipod off to start. I don't have any sandbags to use of the front of the rifle, just a small one for the stock. Will a backpack stuffed with a sweatshirt or something work, or would that potentially induce more accuracy problems?
 
I've shot off all kinds of things.

Too hard, soft squirmy unstable bouncy.

Fillings have been cat litter, airsoft bb's beans rice and wadded up old shirts, sand and dense foam blocks.

Bags end up being personal and a fierce fan boy shit show on here.

Stuff it with some extra so you can remove some at a time till it feels the best you can get it.

It should be good enough to let you know if the bipod was giving you problems.

I've been shooting over 50 years and would still rather shoot off of a dead cat than a bipod. Just never got comfortable with one enough to prefer it.
 
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You have been given a lot of great advice here. I tried to read everything, however, I started skimming through and so if I repeat something, my apologies. My thoughts in the order I would try them:

1. Gas Tube. The gas tube touching the barrel nut would cause your problems. Check to see if the gas tube is touching any portion of the barrel nut and/or the hole where it enters the upper receiver. If it is, then you need to swap out with a different brand of Gas Tube or change the alignment of the gas tube. I didn't see what brand you are using, but I prefer the BCM brand because it has a higher bend and starts the bend earlier than most. If you ever shoot Geissele rails then you will definitely appreciate the BCM Gas Tube. It is the only one I have found that clears the longer barrel nut that he provides. I am sure there are others, but BCM has always worked for me.
2. Ammo: I have had terrible luck with shooting ELD-Ms in my ARs. They don't shoot well. I think it is because the tip gets damaged on the feed ramp but I am not sure. I suggest trying a factory BTHP if they are available.

3. Gas Block: I would use a non-adjustable gas block. I use a lot of AERO products, however, I do not like their adjustable gas block. I have used two, and both were finicky and didn't seem to work well. Try one of their non-adjustable.

4. Bolt: If the bolt was properly head-spaced, this shouldn't be your issues. In my experience, I have found that bolt lock up issues (fouling/etc) will cause flyers, but not necessarily consistently bad (3" groups). That said, I would buy a good mil spec bolt and try that, because you may have a bad bolt. Others have recommended JP. They are very high quality. You can't go wrong there.

The AR platform should easily shoot sub MOA with the components you have listed. Good luck.
 
Lots of good advice so far, but one thing to consider is magazines and meplat presentation to the feed-ramp.
Whatever the magazine capacity, reduce by 1 round.
Check feed by inserting a full (-1 round) magazine with bolt locked to rear.
Release bolt to chamber top round, remove magazine, and eject the chambered round into something soft.
Examine the meplat (tip) of the projectile to see if there's deformation or scoring on the ogive.
Repeat from opposite side of the magazine.

If they both look good, do the same thing, but fire one round, allowing the rifle to cycle. Eject that round and examine the meplat/ogive for deformation. Check both sides.

I do 5-10 rounds per side, topping the mag off after each iteration to keep it at max capacity per side.
If you don't see anything up at max capacity, work down through the mag stack to see if there's anything weird going on.
If you have tracked a group pattern that correlates to a position in the mag stack where you see a consistent difference in group patterns, check there after the full mag checks. This could be caused by some kind of binding/obstruction/lazy mag rise at a point in the follower travel.

I will also check group patterns with only 5 rounds in the magazine, 10 rounds in the magazine, 15 rounds in the magazine, etc, to see if I see any correlation, as well as 15-25 round single shots on separate targets to see if there's any pattern to deviation from group average center.

Not saying that your problem *is* magazine related, but it is an identified weak point in 6ARC ARs at present.
 
Hi everyone, I'm looking for advice on an AR15 that I can't get to shoot. It's about 1.25-3MOA and very inconsistent. It's chambered in 6 ARC and it's a home build. I'm also not claiming to be an expert shooter but I've built 3 other AR15s and one AR10 that all shoot less than 1 MOA.

The rifle in question originally had a Shaw barrel and had the same issues. I tried disassembling and reassembling making sure everything was torqued correctly etc. I finally replaced the barrel with a Proof stainless barrel but I'm still having finicky results. I've got about 60-80 rounds on the new barrel.

Any suggestions on what I should check next? It does seem to have a little bit more vertical dispersion than horizontal so I'm almost wondering if it could be something in the handguard, barrel nut upper receiver chain. I have tried to put consistent pressure on the bipod, so off that's the issue, then this gun is far more sensitive than any other I have.

Other parts are BCM stripped upper receiver. Alexander arms bolt, Areo precision handguard. Aero lower parts kit, aero adjustable gas block, geissele SSA-e trigger, and Primary arms 4-14 R-Grid scope.
A tuner could suck em in . worked for me
 
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Could be a lot of things, but check the inside of your Aero handguard to make sure you aren't able to apply pressure to the barrel and get your gas block to touch. Those ATLAS handguards can pretty easily make contact if you are running a barrel that has a gas block larger than .750".

Again it could be a lot if things, but I once fought a situation like yours and finally figured it out after swapping two barrels. Same thing can happen if you let your M-LOK T-slot nuts make contact with the barrel too.
I never even thought of this. I have an AR with a new Proof barrel and remembered how the gas block was interfering with the m-lok nut for my bipod. I was so fixated on getting the nut tightened that I didn't notice that I had tightened the screw into the gas block. When I loosened it just now, the handguard moved slightly. I haven't shot it yet with the new barrel, but I bet this just saved me some mystifying aggravation.
 
That pressure point will screw you over. Nothing should touch.

I had a stock on a bolt gun that when I used a bipod it went berserk, the screw for the bipod would touch when I loaded it up.

On my ar's I moved my rails back till the screws were behind my gas block.

I love my EC Tuner Brake to death but it probably won't correct mechanical problems .