Hey all. I need some help identifying my A2 20" Upper. It has no manufacturing name but the shop said it was a FN upper. The barrel has no markings.

The right side of the front sight is stamped: F01 (then a circle type mark) 2

The top right of the Upper, directly in front of the rear sight: Keyhole shape stamp with three vertical dots.


Question: Is there anyway to positively ID the upper? Also is there any way for sure to tell if it is chambered for 5.56 or .223? I am assuming that it is a 1:9 twist.

Thanks!

That is a forging mark, not a manufacturing mark.

I doubt that it is a FN since they only make parts for the military.

The barrel
has [b]NOTHING[/b] for marks?

On top down by muzzle.

Should have something to tell you what it is..

Nothing else except that front sight.
[img]http://home.nc.rr.com/stonewallair/UPPER2.gif[/img]
The Barrel is completely clean of any markings. This upper was mated to a Rock River Arms lower when I bought it on consignment.

Thanks for your help!

Well by process of elimination, we know it is not a

1. Colt
2. BM
3. FN

so after that I am clueless.
Sorry.

Thanks All! Great info!

I'm going to try and find some Federal XM193, Winchester Q3131A, or the IMI M855 tomorrow at the Gun Show in Raleigh and see if it feeds OK. I have fired a few boxes of Winchester 40 round White Box .223 REM 55gr FMJ (USA223R1VP) and S&B 223 REM 55gr. (M193/No2903 Green Box) so far. Groups were good and ejection was positive. We'll see how she handles the 5.56 tomorrow.

Thanks again!

Good info.

Ok here goes. I got an assortment of ammo at the gun show.
Federal XM193 5.56
Winchester Q3131 5.56
Winchester White Box 40 rnd. .223 55gr
Wolf .223 55gr

25 Meters to sight in. Firing seated using improvised rest. Slow fire using 6" black discs as targets. Rapid fire at a M6 Silhouette. Fired from rest and standing mostly Wolf, 3 rounds as fast as I could, Paused, grin , repeat , grin , repeat......
Total rounds fired: 300
Temp: 83
Wind: nil

All rounds fired with no feeding or ejecting problems. Rifle allowed to cool after each 100 rounds for 10 min. The Winchester white box .223 and Wolf ejected quite a bit farther rhan the Federal and Winchester 5.56. As usual the Wolf was the smelly round of the lot. The Fed and Win 5.56 had more kick. I have attached pics for examples of groups per each ammo type. The Fed/Win 5.56 performed well , as expected. So did the Win. white box. The Wolf ammo surprised me. For a cheap plinking ammo it did alright. I will be doing more long range testing this weekend. I will assume that out past 100 meters the Wolf will start to show its weakness.....Stay tuned...

[img]http://home.nc.rr.com/stonewallair/TARGETS.JPG[/img]

[img]http://home.nc.rr.com/stonewallair/RAPID.JPG[/img]

lol, yeah i know. [:D] I was having too much fun with my new toy. I was only concerned with fuction and groups. I need to go out this week and dial her in.

The upper is also not an Oly.