They're bent or canted or otherwise just off, at least as near as I can tell. I'm 2 for 2 different retro 20" 1/7 A1 barrels that require just about full left windage and a lot of down on the front sight post to zero at 50 yards.



That's how much left windage



That's how deep the front sight needs to go - not as bad as the last barrel I had to return but it's still significantly turned in compared to how it should be - it makes me think these are unmarked F front sight blocks being installed on these things...

Like I said - this is the 2nd barrel with the exact same issue. The other barrel, I tried in two different uppers and it zeroed identically between the two of them; same windage and depth off.

I took one of the receivers I used for that testing, mechanically centered the rear sight and rebarreled it with a different barrel - it zeroed at the range with one click to the right and didn't need to touch the front sight at all. That tells me it's not me messing it up somehow and it's not the receiver being out of spec (I tested with a surplus Colt M16A1 upper as well as a new Brownells BRNA1 upper). This was also tested both with 62gr M855 (since it's a 1/7 barrel; those photos are from using that ammo) as well as Igman 55gr ball. Same results between them.

Anyway - this one will be back in the mail to you on Monday morning being returned. You guys should probably pull any barrels from this batch and do a little QC on them, or maybe just kick them all back to the manufacturer.

It's really kind of soured me from buying any other Brownells-branded barrels at this point I was looking at getting a mid-length carbine barrel but if that's going to be as off as this one is...no thanks. I don't know who your vendor is for these but I'd highly suggest finding another one

I've sent an email to the Product Team for them to check the barrels out.  I referenced this thread and the other one you were participating in.

Awesome, thank you! If you guys don't find anything wrong with them and can barrel them up and they're more-or-less centered and perfect, then please let me know what the hell I'm doing wrong Like I said I don't think it's me doing something incorrect, but there's always a chance it's a me problem

My 20” retro barrel was F*cked like this except it would not zero all the way left. I had to take it to ADCO And they fixed it overnight for $50 bucks.

Shame  on Brownell’s. I do not respect your QC process. $200+ for a barrel and I had to have a second gunsmith fix it.

How did they fix it again? (forgive me, if you mentioned it in the other thread that I can't find, I can't remember it )

I mean the front sight block appears to be in line and not canted or anything? Certainly nothing obvious.


I guess it's also worth mentioning that this is specifically the 1/7" barrel. I'd like to build around that because I'd like to shoot modern (62+gr) rounds in it. If the 1/12" barrels don't have this issue...I mean, I can live with keeping a stockpile of 55gr around just for that...but I'm now kind of hesitant to buy one of those just for it to have the same issue..

I've got the Product Team involved with this, so they'll be looking into it.  I'll share any information I receive.  

Don't be afraid to use our "Guaranteed. Forever." return policy if it's not up to snuff!  

Guaranteed. Forever.

Wow, kind of amazing honestly! I didn't really think the issue was going to be so consistent that you'd run into it again with the new barrel. In to hear any details about what the cause might be.

This seems to have been going on with these barrels since the beginning of the Retro line.

Tag.

I don’t have time to explain why this will work just try it.

Loosen the barrel nut. Allow the barrel to twist right in the direction of tightening as much as possible… most upper receivers have a slight amount of play between the barrel extension stud and receiver.

Most have issues with the sights being more right not left.

Best of luck

Basically it's a problem with the assembly, not the actual components?

The upper receiver face is likely not square. Having it trued, or doing it yourself, may fix the problem.

I purchased a retro AR-15 from Brownells and I had to machine the front sight post hole deeper to get enough elevation to obtain a zero. IDK if my upper receiver face wasn't square, which may have caused the same problem you have, just in a different direction.

...Did you actually read my post? I'm guessing not and just decided to chime in?

Same as previous - did you actually read my post? If you just skimmed it, re-read it again...2 barrels, 2 uppers, one of which had another barrel on it at one point and the other barrel zeroed just fine. Massive AND windage elevations.

Seriously, I swear, people here stopped reading things and decided they just need to chime in for post counts

The FSB issue can be confirmed with a measurement but  a “F” post is a pretty good guess. I don’t know anything about production lines but it seems a batch could have been run at “F” spec, never got stamped, and then were assumed to be standard.

If that’s the case, the windage issue is unrelated to the elevation issue. Could be bent barrel, bad index, over torque, or canted FSB.

I wouldn’t dismiss his theory right away though.  The two issues could be unrelated. The elevation thing is just out of spec regardless. Way off.

ETA: Bent barrel is one thing that would cause both, but seems least likely.  But I think I once saw a video of FN production line and the guy was whacking a barrel with a mallet for some reason.

@Brownells

Who is the mfgr on these barrels currently?

I have three of their retro barrels, two of which are in my parts box unbuilt as of yet.

I just checked them, one appears to be perfect and the other looks like it’s canted left.

Same situation here. I tried correcting by filing the indexing pin because I'd already had JT perm attach the muzzle device to 16". They wanted me to remove it and asked why there was a crush washer when it was their own XM177 hider/grenade ring. I got disgusted with it and its sitting in the corner.
The 20" I got right after that one while it was off for work is good to go.

It isn't much a barrel issue as a locator pin issue. I have a friend with a Brownells A1 upper and retro barrel. There was an unacceptable amount of play and torqueing the barrel nut caused the barrel to shift (locator pin moving and causing the FSB to angle). I used steel epoxy to lock the locator pin to center in the notch in the upper receiver. This resulted in the FSB staying vertical and properly positioned.

Either the notch in the upper is too wide, or the locator pin on the barrel extension is too thin.

Interesting… None of mine were like that, but all my Brownells 20" A1 barrels and A1 uppers were from a few years ago. However, I did have a Brownells C7 upper (it was also purchased a few years ago) that I had to return due to it's indexing pin notch not being top dead center. Of course it caused the FSB to appear canted, and the bolt lugs were impacting the barrel extension lugs.

My set up for barreling locks both the upper and barrel extension together so nothing can twist with the barrel nut unless I want it to.