ar 15 9mm/223 ahhhhh!!!! help

Discussion in 'AR-15 Discussion' started by moneymaker17, Nov 2, 2010.

  1. moneymaker17

    moneymaker17 New Member

    correct me if im wrong but i thought ar 15 lower receivers are universal. but alls you need is the upper for the 9mm conversion.

    i saw on a video when this guy switched from a .223 upper to a 9mm upper within 4 seconds.?
    if i want to build a 9mm ar 15 what will i need to get?
  2. Shihan

    Shihan Well-Known Member Lifetime Supporter

    You could always just get a Hi-Point 995.:D

  3. Dillinger

    Dillinger New Member

    An AR-15 lower will shoot both the 9mm and the .223/5.56mm round.

    You will need two different types of magazines. One for each round.

    You will need at least one upper, but you will need two barrels, one for each round, along with the bolt carrier group for at least one round that you can switch back and forth. I think you also need a hammer for each unit, but I can't remember for sure and it's late, sorry.

    However, you may need to fine tune your buffer and buffer spring for the difference in the power of the cartridges.

    The easiest way is to have one fine tuned lower and have two uppers:

    (1) dedicated to shooting .223/5.56mm rounds

    (1) dedicated to shooting 9mm rounds

    Then you change two pins and you are set to go to the races, baring the same hammer can work for both rounds. :D
  4. M14sRock

    M14sRock Active Member

    You will also need the magazine block (that drops in from above) to fill the mag well. Brownells has the whole conversion kits. And some of the conversions are designed to work with the .223/5.56 hammers which is very nice. On those, it is wise to have the carrier ramped to work with the 5.56 hammer, though.
  5. kenhesr

    kenhesr New Member

    This is the easiest way I've found, I'm not saying its the best way!, just the easiest for me. There are a lot of 9mm AR platforms out there and I'm sure everybody likes theirs the best.

    I built a complete AR in 5.56 and bought an OLYMPIC ARMS 9mm upper for it, (bottom rifle in pic). The OLY can use the SOCOM block & 32 rd surplus Sten mags. You can buy mags from OLY so you don't need the SOCOM block, but they are pricey. Also, It is made to use the standard AR-15 5.56 hammer and buffer spring.

    This is a pop two pins, switch uppers and go set-up. I have many K of brass & steel cased 9mm thru mine with zero problems.


    Another thing you might need is a little red wagon like you had as a kid to haul your 9mm ammo around. These are SUPER fun to shoot and love to eat ammo! A dedicated .22lr upper is great too, but thats a whole different discussion.

    Good luck with the build, Ken