A2 carry handle sight - windage adjustment. How much is too much?

[markm]

You mentioned above what the military deemed as 'acceptable' I believe. And you also mentioned selling one that you bought that was 10 clicks off? (that still falling inside of what you said the military would accept)

I read somewhere where there's a acceptable windage from mechanical ZERO. But I would NOT have such loose tolerances for my guns. I ABSOLUTELY would not sell a POS receiver to anyone. I'd never pass garbage on unless the buyer knew it and still wanted it.

Plenty of other guys around here that would be able to diagnose the problem and possibly correct it on their own without selling or returning anything...

Point being - Depending on the problem and the severity - Sometimes that stuff can be adjusted / tweaked to the point where everything is perfect.

All of the parts we are discussing have 'tolerances' and there is no shame in having a shim here or there to make things closer to being perfect for a customer or an owner.

My point is simply that if any guy ON THIS SITE were to buy an AR and find some booger eater fix on the gun when the took it apart, there would be a witch hunt on that manufacturer. And rightly so! These silly mods are totally unacceptable in my opinion.

[markm]

I've corrected the sights on a considerable number of AR's by loosening the barrel nut, moving the barrel and tightening the barrel nut to correct torque.

I tried that with my shit upper, and it didn't work. In fact, truing up the receiver actually put it another click or to off to retardville.

[AndyLate]

You just need a lead hammer and a railroad tie with a 1" hole in it...

Andy

[T2C]

I tried that with my shit upper, and it didn't work. In fact, truing up the receiver actually put it another click or to off to retardville.

Who made the upper?

[markm]

Who made the upper?

Here's the POS in question. I found it. Like I said somewhere in the thread, It's supposed to be a Bushmaster bought stripped from who knows where.

It's WORSE than I remember 16 clicks off mechanical ZERO to get the turd on target.

[HKGuns]

Here's the POS in question. I found it. Like I said somewhere in the thread, It's supposed to be a Bushmaster bought stripped from who knows where.

It's WORSE than I remember 16 clicks off mechanical ZERO to get the turd on target.

Looks like you rescued it from a dust devil.

[DG23]

I tried that with my shit upper, and it didn't work. In fact, truing up the receiver actually put it another click or to off to retardville.

Kindof funny how you see no problem with having to true a receiver face but it becomes a 'turd' if you need to adjust the index pin notch a slight bit...

lol!

PS: If your receiver tool is the one from Pacific can I borrow it for a few days? Have 3 that would not hurt to be done. Have my own lapping compound already... Will gladly pay all the shipping back and forth.

[neil0311]

Without getting too long winded here, bought a complete M16A4 style rifle last spring from a mfg everyone would recognize. Couldn’t get a BZO. Sent the upper back and the mfg said they adjusted the front sight which I assume was canted.

I can zero the rifle now (using a Marine style 25 yard BZ), but doing so requires me to crank the windage adjustment on the carry handle rear sight almost completely to the left (there are a couple of clicks left). The POI is on target.

Is that acceptable and in spec, in terms of quality that someone should expect for a AR-15? Am I being too picky? If it zeros, just be happy and shoot it?

So I got an RMA and sent the upper back. Requested a replacement, but obviously I can only ask.

Just received this from PSA which is who assembled and sold it. I wasn’t going to say who it was, but figured WTF? If they don’t want me saying, then don’t ship products that aren’t built correctly.

“ The following repairs were completed on your Palmetto State Armory product:

Put the FSB gauge on the upper and had to make minor adjustments to make center.”

Does that sound plausibly correct? Or are they just jacking me off?

[T2C]

Here's the POS in question. I found it. Like I said somewhere in the thread, It's supposed to be a Bushmaster bought stripped from who knows where.

It's WORSE than I remember 16 clicks off mechanical ZERO to get the turd on target.

16 clicks is entirely too much off center IMHO. Most uppers I've seen have the rear sight adjusted way left of center to zero.


Here is something I do to verify the front sight is plumb when the receiver is level. On a carbine or rifle with detachable carry handle, I remove the carry handle and put a 36" or longer straight edge on the flat on top of the receiver. If you have a fixed carry handle, place the straight edge on the flats on the bottom of the upper receiver. Then I shine a bright light through the straight edge and FSB, transpose the shadow on a plumb line I have drawn on the wall in my workshop, then level the shadow of the straight edge. It's easy to see if the straight edge is level when you look at the shadow on the wall. The shadow of the FSB will show you if it's canted. It's old school, but it works. I learned this technique using two straight edges to verify proper index when installing barrels on M1 Garands, 1903 Springfields, 1917 Eddystones, etc.

A 13/64" drill rod will tell you if the barrel is bent. The rod is .203" in diameter and the minor diameter of a .223 caliber bore is .219". That gives you 0.016" clearance. If the rod drags inside a 16" barrel, that tells you the barrel has more than 0.001" deflection per inch. Make sure the barrel is squeaky clean or you will get a false reading. If the rod will only go halfway down a clean barrel, you have a problem.

I've shot old Mausers with bent barrels that shot good groups, but the front sight was way off center. I can think of no reason that should be tolerated on a modern AR-15. On a modern firearm, produced on modern equipment, IMHO the rear sight should not be more than 6 clicks from center when zeroing on no wind day, using your dominant eye. If your dominant eye is the left eye, and you shoot right-handed, the rear sight will most likely be off center to zero.

Armalite used to sell a clamp on FSB that made it easy to zero windage. Fire a few shots, move the front sight base, fire a few more shots, repeat as necessary. When you're happy with your zero, torque down the screws.

[the AR-15 Junkie]

Last summer I designed a cheap under 70$ front sight block "can"t gauge, then gave away FREE the design and part#s.

I checked about 18 Colts, all were perfect but 2. Those 2 had aftermarket rails. 16 Colts with pinned on FSBs were all perfect. The majority of the videos on my Youtube is checking FSB cant.

Here is a couple of vids of it being used and the How too Video, to build your own.

https://www.youtube.com/watch?v=FZeyoa15u3Y

https://www.youtube.com/watch?v=rQMz-WUrgtQ&t=176s

https://www.youtube.com/watch?v=HWpvAuT4NIE How Too Build video!