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Thread: FN 20" A4 upper...FNMI marked?

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    FN 20" A4 upper...FNMI marked?

    So I just picked up a 20" FN A4 upper w/ Aero A2 lower, not a fan of the lower but paid $500 for the entire rifle. Figured I would sell the lower and get a Knights lower or Colt. Just wanted some info on the upper I bought.

    So the barrel has FNMI MP 1/7 markings, the receiver has "F & keyhole markings". Just wanted to get some info on what exactly and where exactly this upper came from?

    Thanks
    Mike

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    Although this is not a vintage AR related post, I will say that the upper receiver is FN. The keyhole forge code means that the forging was produced by Cerro Forge. The stamped F means that the machining and anodizing was done by FN. Most likely, it is a surplus upper assembly. There is no way to know where the assembly came from. AS far as a lower, I would recommend looking into a McKay Enterprises or PSA Stealth lower. Neither of these have logos. Of course, if you wanted to go another route, you could buy a 80% lower, have it custom engraved with FN markings, mill it, and have it anodized. I would not put a FN upper on a Colt or KAC lower. Another idea is to contact Black Creek Precision to see if they will make you one of the M16A4 marked lowers that a few of us had done over a year ago.









    "A Bad Day At The Range Is Better Than A Great Day Working"

    USMC Force Recon 1978-1984
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    M16/AR15 shooter since 1978, gun collector and AR builder since 2004

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    Only thing I can tell you is the receiver is FN and that the newer barrels are marked with the FN cage code not FNMI, also receiver should not have the M4 cuts. If in decent shape $500 was a killer deal, not sure why you want to swap lowers, Aero's are decent quality.
    “The Trump Doctrine is ‘We’re America, Bitch.’ That’s the Trump Doctrine.”

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    Quote Originally Posted by mack7.62 View Post
    Only thing I can tell you is the receiver is FN and that the newer barrels are marked with the FN cage code not FNMI, also receiver should not have the M4 cuts. If in decent shape $500 was a killer deal, not sure why you want to swap lowers, Aero's are decent quality.
    Yeah I figured for $500 it was a good buy, it also came with a KAC rear backup sight and carry handle.
    I agree Aero products are good quality. The lower that came with it has a UTG A2 buttstock and cheap Anderson LPK. So I would like to upgrade the LPK, and find the proper colored A2 stock. I figured while I'm at it might as well buy a M16A4 marked lower. I see that Aero has the M16A4 lowers complete and in stock, I might just order one of those!
    Last edited by mykdee; 10-12-18 at 08:32.

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    Quote Originally Posted by Renegade04 View Post
    Although this is not a vintage AR related post, I will say that the upper receiver is FN. The keyhole forge code means that the forging was produced by Cerro Forge. The stamped F means that the machining and anodizing was done by FN. Most likely, it is a surplus upper assembly. There is no way to know where the assembly came from. AS far as a lower, I would recommend looking into a McKay Enterprises or PSA Stealth lower. Neither of these have logos. Of course, if you wanted to go another route, you could buy a 80% lower, have it custom engraved with FN markings, mill it, and have it anodized. I would not put a FN upper on a Colt or KAC lower. Another idea is to contact Black Creek Precision to see if they will make you one of the M16A4 marked lowers that a few of us had done over a year ago.









    Nice rifle!
    Oh, Semper Fi!

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    Quote Originally Posted by mykdee View Post
    Yeah I figured for $500 it was a good buy, it also came with a KAC rear backup sight and carry handle.
    I agree Aero products are good quality. The lower that came with it has a UTG A2 buttstock and cheap Anderson LPK. So I would like to upgrade the LPK, and find the proper colored A2 stock. I figured while I'm at it might as well buy a M16A4 marked lower. I see that Aero has the M16A4 lowers complete and in stock, I might just order one of those!
    For an A2 buttstock, I like the ones offered by White Oak Armament. I have a couple of those in use.

    https://www.whiteoakarmament.com/cat...stock+Assembly

    WOA also carries some good quality LPKs.

    https://www.whiteoakarmament.com/sho...ver-parts.html
    "A Bad Day At The Range Is Better Than A Great Day Working"

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    I was actually looking at the White Oak A2 stock kit. What about Rock Rivers A2 kit, any good?
    I also found a LGS that has the Aero M16A4 lowers in stock for $79. I might go pick one up today.
    Thanks for the responses so far!

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    Quote Originally Posted by mykdee View Post
    I was actually looking at the White Oak A2 stock kit. What about Rock Rivers A2 kit, any good?
    I also found a LGS that has the Aero M16A4 lowers in stock for $79. I might go pick one up today.
    Thanks for the responses so far!
    RRA A2 stocks are good to go too.
    "A Bad Day At The Range Is Better Than A Great Day Working"

    USMC Force Recon 1978-1984
    US Air Force Res. 1995-2004 (Air Transportation)
    M16/AR15 shooter since 1978, gun collector and AR builder since 2004

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    Does the WOA buttstock have an aluminum buttplate and door, or is it plastic?

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    If you have the ability to cut an 80% and can find a good laser guy that is my recommendation.


    As mentioned above the current generation barrels are cage code marked. My guess is you have an early A4 or possibly an A2 barrel. Is your front sight F marked?


    This is my USMC A4 build. Everything is FN but the lower and the accessories.
    Last edited by JPurp; 10-13-18 at 17:24.

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