Gunsmithing Does the rail need to line up perfectly straight? AR15 build question, should I worry?

[Long Range]

I would like like your thoughts here, I built a 300 blackout rifle with an 8" Vseven barrel.
Using an Aero precision rail and upper receiver.


I am using a blast can and the rail opening is only about 1.2mm wider than the blast can. This would give me about .6 mm on both sides of the muzzle device.

I noticed that the muzzle device is slightly closer on the left rail side than the right rail side. I would say about .4mm gap on the left and .8mm gap on the right side. You can visually see this if you look closely because there is so little clearance.

I'm not sure what causes this but it is probably the rail or barrel nut not being perfectly straight.

Assuming the rail or maybe the barrel is off by up to .4mm, would this be too much to use iron sights? Is this an issue not being perfectly straight? Could this affect accuracy?

Do you think most rails and not perfectly aligned with the barrels?

Here are some pictures so you can see my setup and how close everything is.

The bottom two pictures you can see that there is a little more space on one side than the other.

Thanks for any advice here, I really need to know if everything needs to be perfectly straight or is this a non-issue and most guns are probably out of alignment like this?

This is the left side and you can see the blast can is a little closer to the rail.

This is the right side and you can see there is a little more space between the rail and the blast can.

 

[GH41]

Are you using a crush washer? If you are take it off and see how it looks without it. If that doesn't help write it off as tolerance stacking.

 

[supercorndogs]

That blast can is going to contact the hand guard when you are firing. It will not be good for accuracy. Not that it matters for what it is.

 

[Cornerstonearmory]

Could be the aero rail clamping system. Never was a fan of that system. I’d start there, loosen, realign and retorque.

 

[Long Range]

That blast can is going to contact the hand guard when you are firing. It will not be good for accuracy. Not that it matters for what it is.

Why will it hit if its not hitting now?

 

[Cornerstonearmory]

Why will it hit if its not hitting now?

Bc barrel whip. That barrel, upper receiver and handguard will flex all over the place when the bullet leaves the muzzle, and it being that close just isn’t good in general.

 

[Long Range]

Bc barrel whip. That barrel, upper receiver and handguard will flex all over the place when the bullet leaves the muzzle, and it being that close just isn’t good in general.

I see your point. Yeah, I may get a different linear compensator for this gun.

 

[supercorndogs]

I have never had a gas block that close that didn't cause problems. Shoot it and see. It might not. I have never had a barrel that short.

 

[ken226]

Handguards that use a pinch type setup to clamp onto the barrel nut are easy to misalign.

I like to use a long picatinny riser as an alignment fixture.

Clamp the rear half onto the upper, and the front half onto the handguard to hold them in alignment, then tighten the handguard pinch screws.

 

[Cornerstonearmory]

Handguards that use a pinch type setup to clamp onto the barrel nut are easy to misalign.

I like to use a long picatinny riser as an alignment fixture.

This is a nice jig but a little over the top. To the OP, no need to get a new comp or rail but along the lines of the alignment system above, just get some soft jaws (aluminum angle stock) vice clamps and with rail loose clamp it in the vice where the rail and receiver meet. That will aid alignment greatly.

 

[ken226]

That's a run of the mill picatinny riser. A million like it are about 12$ each on eBay or Amazon. A small stick of aluminum angle from Ace hardware cost almost as much.

 

[hermosabeach]

some high speed slow motion on barrel and gun movement...

while the blast can is a sweet look, I would be shocked if you do not get inconsistent / accidental contact between blast device and the free float tube....

it could be ok or it could be someone randomly placing a finger on a guitar string while being played and messing up the harmonics/ vibrations of the string...


--
to answer the question, check each part... are the threads of the barrel cut concentric to the outside of the barrel or the bore?


For a suppressor, threads should be cut in line with the bore...

for your set up, one might need to turn the outside of the barrel to be concentric with the bore...

what is the specs for the linear comp? are the threads cut in the center of the device and perpendicular to the bore within X ten thousands.