Frustrating day with my 11.5 inch upper

[readyeddy]

I'm no gunsmith. If I bought a complete upper and it shot like that, I would send it back.

 

[Inebriated]

FSB straight and without cant?

Barrel visibly appear straight?

Upper receiver itself appear straight? I would set the upper flat on the counter and put a square on each side... should make it evident if it's straight. Same for the FSB.

 

[Casefull]

Dr. Rob. It is not the barrel, it is the sights or something is loose. It is never the barrel when things are "way off".

 

[BSA1]

I am not trying to be a smart aleck but what is the point of a 11.5" barrel when you have to hang 4.5" tube on the end? I assume it is to meet 16" legal length. Hanging a metal tube with the extra weight on the end seems to me that it changes how the barrel vibrates as the barrel passes through it.

It's a shame you can't remove the tube and shoot the gun without it. I am looking forward to hear what you discover.

 

[Dr.Rob]

The point is I wanted an XM-177 looking shorty without the tax stamp, an extra 4 inches of barrel would weigh more than the flash hider. If I decide to SBR it later I still have that option, it will take TWO stamps to make it a 'legit' XM--one for the short barrel, one for the supressor. I have three other AR's for various purposes. This one is meant to be a short fast handing carbine just for fun the heck of it.

This was NOT purchased as a complete upper. It's built from a pile of parts. The barrel FSB and flash hider were purchased as a unit from Tony's Customs.

 

[readyeddy]

Ok, try putting the rear sight on a different upper and sight in. If the other upper also shoots way off, then maybe something is wrong with the sight. If you hit paper, then continue the process of elimination.

 

[MachIVshooter]

Ok, try putting the rear sight on a different upper and sight in. If the other upper also shoots way off, then maybe something is wrong with the sight. If you hit paper, then continue the process of elimination.

It's an A1 upper

 

[Dr.Rob]

I will try the suggestion with the squares tonight.

 

[Holescreek]

Saw that on a friends rifle, front sight was pinned on cock eyed.

 

[Dr.Rob]

It is difficult to photograph (I am not square to the subject) but I can't see any canting. I need another inexpensive square and a third hand to check with calipers.

 

[readyeddy]

I think I'm starting to feel frustrated.

Isn't the front site tilting to the left? The top of the hand guard looks square, but the sight looks to be tilting to the shooter's left (my right). This would send the shots wide to the right.

 

[MachIVshooter]

Looks like the sight is, in fact, canted. You have the front sight aligned with the squares, and it appears the the rest of the rifle is rotated CCW if looking from the front. That would require lots of left windage to correct.

 

[Inebriated]

I think the front looks fine, though it could be the angle... a minor cant (one needing calipers to detect) probably wouldn't put you off the paper at 25. If it doesn't stand out to the eye, it's probably not an issue. Still, worth being sure, since you're troubleshooting now.

I guess it could be the rear sight/receiver itself is off a bit, but then again, it seems like that too would jump out without even having to check.

If that too checks out, then I would really look hard at the barrel... I mean, that's really all that's left.

 

[bfoosh006]

I also think something is loose. I would double check the barrel nut, tightness as well as the face of the receiver and AR15 barrel extension for a burr or such.
Also how loose is the fit on the barrel extension alignment pin to the receiver ? If the fit is "sloppy" tightening the nut may have canted the whole barrel assembly... FSB included.

You should be able to shim that possible issue.

Look for possible cracks in the receiver face.

How was the barrel "flash hider / extension" attached ? I mean the bullets aren't nicking it in anyway are they ?

The front sight base is tight , right ?
Maybe the taper pins need a little more firmer setting in.

 

[Dr.Rob]

I am going to have to wait a few days to suss this out.