how to identify an upper

[jacobjrl76]

Perhaps an ar-15 guru can help me out. I purchased an ar-15 upper at the gun and knife show. Got it home and the sights are all screwed up. The fella that sold it to me told me it was an FN upper. Come to find out FN does not make uppers. I thought this was kind of funny when I bought it. Anyway neither hear not there.
My question is, Does anyone out there know how to identify an upper ? I can't find any markings of any sort ! Any help would be greatly appreciated.
Thanks

[Marlin]

Pic's would help. :wink:

[jacobjrl76]

The flare launcher is extra and the lower is a bushmaster. The upper came with both handguards. The upper did not come with charging handle and bolt carrier.
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[The1andOnlyKC]

No markings on the bbl either? Like just infront of the site base?

[Great-Kazoo]

what's the mark on the upper? carry handle r/side just in front of th erear sight. hilite it with a white crayon.
and yes FN does make uppers. they even have a web site
http://www.fnmfg.com/

and why do you feel the sights are "all screwed up"?

[kwando]

did you pick that up at the last crossroads gun show?

[The1andOnlyKC]

[whispers to kwando] Pssst He's from Mississippi :wink:



And +1 on what Jim said whats wrong with the sites?

[jacobjrl76]

That is what got me, there is no mark in front of the rear sight. My Bushmaster upper does have a mark on it. This one doesn't.
The rear sight is loose as loose gets. It sits cockeyed and as you turn the sight up it striaghtens up a good bit. Also the rear sight starts out on the 500 meter mark instead of the 300/800 mark. I picked this up at The Ernie Bean gun and knife show in Jackson Mississippi about 4 or 5 months ago. I took it to a local gunsmith and he recomended scrapping it. I was going to try to figure out who made it and see if they could make the sights good.

[Marlin]

I could suggest, maybe just get a new rear sight base, it is an A2 right?

Have You shot it? Other than the rear sight problems, Does it hold decent groups?
How does the barrel and throat look? Is the rifleing in good shape? does the throat look eroded? Do you have access to headspace gauges?

If everything looks good, and its just the rear sight, try a rebuild or replacement.

Chances are, If You can't find any marks on it it's way down on the food chain, and whoever built it may not have a warrenty or, a very limited warrenty on it.

Try this first, Flip up the rear sight, so that the long range is up. You'll see a hole in front of the sight. Take a 1/16" allen wrench, put it in the hole and loosen the screw. LEAVE the wrench in place, rotate the bottom of the sight in the directon of the 3/8 mark, going off mine try about 7 clicks. tighten the the screw, the see if the 3/8 mark is in the right place, it should be bottomed out. if not just do it again.

[The1andOnlyKC]

Sounds to me like the rear sight was screwed with by someone who couldnt figure out how to put it back together.

Try what marlin suggested and report back.