I recently acquired an Armalite A2-type upper assembly with a 14.5" M4 profile barrel. According to the vendor I bought it from, it was a police trade in upper. It is currently being modded to 16" non-NFA barrel length. I contacted Armalite, but they said that they have not offered a 14.5” barreled upper or rifle.
So, with that in mind I am trying to identify the barrel manufacturer and twist. The upper receiver has M4 cuts and a fixed carry handle with 8/3 A2 sights. The bore and chamber are chrome lined. The only markings I can find on the barrel are an “A”, “4”, or inverted “V” at the 12 o’clock position looking at the chamber end, and under the slip ring / barrel nut and gas tube, an illegible number and I think a “M”. The A2 front sight has a forge mark, maybe “4” in a diamond (really fuzzy) and “2”. I also found out that the upper has night sights. It has a trijicon marked blade front sight and two luminous dots on the large aperture of the rear sight. The handguards are skinny M4 type with single heat shields.
I would appreciate any information you can provide. Here is a pic from the vendor; I will try to get better ones later.
Take a close up pic of the barrel and the actual markings on the barrel. Some of the more savvy guys might be able to figure it out if they see the markings.
Could also be a Colt 6921 upper (same as the LE6920 but w/14.5" barrel). I have one that I had a Surefire flash hider (for mounting my Surefire suppressor) put on with a tiny pin and spot weld to make it a permanent 16" o/a length barrel. Made it a neat package - authentic but legal.
Hard to tell from the photo but a lot of LE Dept’s. have the Colts.
Colt barrels to include the 6921 are marked near the FSB and will most likely have C MP 1/7 NATO. Since he hasn’t mentioned those markings I highly doubt it is a Colt.
Okay, I tried a few closeup pics, but my digital camera didn’t want to focus properly sometimes.
Pic #1 shows chamber end marking - A, 4, upside down V?
Pic #2 shows detail of FSB casting marks
Pic #3 shows FSB taper pins and swivel rivet head (a little fuzzy)
Pic #4 I tried to show a slash mark (/) on the bottom of the barrel
Pic #5 I tried to show M and numbers underneath the gas tube and barrel nut
Looked a little closer after seeing a RRA FSB with similar markings for sale on another site, so it may be a RRA R4 barrel. Also I noticed it has 6 grooves, and the letter underneath gas tube looks like a “N” under a stronger light, which corresponds to NATO chamber. Still trying to figure out twist rate. Tried a cleaning patch but it didn’t rotate too well.
Almost all RRA pins are straight and yours appear straight, though it’s hard to tell. Also, most RRA barrels are 1/9 which is most likely what you have. If you want better pics you need to use the macro setting.