AR Issues

[JMcBurn]

So a little background

Aero M4E upper with Quantum Handguard
Aero Gen 2 Lower
Spinta Precision 20" Barrel(really budget barrel)
Cheap Radical Firearms gas system
Hi Speed National Match Trigger
Athlon TALOS BTR
Larue 20 MOA QD mount

So gun was a consistent .6-.9 MOA at 200 yds with low node handloads (maybe 750 rounds through it)

All of a sudden gun is patterning. I think it is the scope and replace it with another TALOS BTR. Take it out again it is still patterning. Start looking it over Barrel has no deformities, but gas block is leaking quite a bit, albeit still functioning properly. So I remove the system even though I don't think that could have been the root cause, while It is mostly apart I decide to check the barrel nut was still tight(it was).

So since then I've purchased new adjustable gas block and new gas system parts.

But I don't think that could be causing all of my issues, so what else could it be or could it be the gas system being crappy?

Maybe bed the barrel with loctite as it does not have the tightest fit? (slightly worried I need to but a new barrel in it and getting a barrel bedded with loctite 243 out would be extremely difficult)

 

[Primus]

Get rid of the junk mount and use a quality 1 piece.

 

[JMcBurn]

I don't think the mount is the issue.The mount seems rock solid, really tight lock up and before these issues arose, it repeated well. (LT745)

What is the likely hood that both scopes are bad?

 

[TonyTheTiger]

Check your bolt lugs for cracks. Is the gas tube binding hard on the gas key? No signs of baffle strikes on the muzzle device or a recently damaged crown?

 

[JMcBurn]

No crown damage, just a little carbon. gas tube looked just fine no binding. Have not looked at the bolt, will take a look at it.

 

[Mute]

What do you mean bed the barrel with loctite? On an AR just torque the barrel nut to the proper weight. Don't loctite. If it shoots inconsistently test one thing at a time. If your cold bore shot is consistent, chances are your barrel just isn't cutting it. If it's a low cost barrel, you can only expect so much performance. If your gas system is improperly installed, you'll have inconsistent velocities (you're lucky the rifle runs reliably), which can lead to inaccuracy. As I said, test one thing at a time. Don't tinker with multiple parts at a time if you want to ID the culprit.

 

[JMcBurn]

I understand the principle of one thing at a time. On correct assembly I am just going to re assemble everything to make sure it is right.

 

[Primus]

I don't think the mount is the issue.The mount seems rock solid, really tight lock up and before these issues arose, it repeated well. (LT745)

What is the likely hood that both scopes are bad?

Larues are known to have issues, its an inferior design that is unpredictable. Has no place on a precision rig.

 

[MSTN]

My most accurate gasser - EVER - wears an LT745. I really don't think it's the mount.

My suggestion:

Clean the carbon out of your barrel. Then examine your muzzle, 360 degrees, in good light, preferably with some sort of magnification. Do you see significant bright copper fouling in a small area on the inside of your barrel?

If yes, then your barrel has blown a chunk of steel out forward of the gas port. This new rough spot is playing absolute hell with the bullet jacket as it passes.

Another manifestation of this will be the fact you can "feel" the gas port much more obviously when cleaning the barrel.

Having access to a borescope would make identifying such a problem much easier.

The problem may diminish with use, if there's no more significant erosion beyond that point.

 

[supercorndogs]

Larues are known to have issues, its an inferior design that is unpredictable. Has no place on a precision rig.

What are their known issues, that would pertain to this problem?

 

[JMcBurn]

Update:

Pulled an optic off another known quantity rifle. Shot 10 shot group at 50 yards that was about 4" in diameter. It was the optic again(sent in the scope for the same issue and was supposed to be replaced, sounds like they just fixed the windage turret indicator on mine and shipped it back) I wish my gen 2 PST would come in so I would have something decent.