ar lower compatability for 308 vs 223

Discussion in 'Large-Bore/Small-Bore Rifle/Shotgun' started by lslubecki, May 10, 2006.

  1. lslubecki

    lslubecki New Member

    Mar 15, 2005
    Can I put a 308 upper on a 223 lower? I found a RRA 223 lower reasonably priced locally and when I asked if a 308 would fit he didnt know. He said it was a 223 lower and didnt have any 308 lowers. I didnt know there was a difference. Thanks for any answers.

    Steve Lubecki
  2. That I don't know. But You can get a .50 kit

  3. wolfgang2000

    wolfgang2000 New Member

    Dec 10, 2005
    Mountain Grove MO.
    The short answer is NO. The magazine well on the 308 is larger than the 223 version.
  4. LDBennett

    LDBennett Well-Known Member

    Dec 20, 2003
    Hesperia, CA

    The magazine well is not long enough for the 308 cartridges. You can do the 50 cal because the conversion is to a single shot bolt action one and the AR lower is used for a handle and as a hammer/trigger system. The magazine well is not even used (the 50 cal conversion is a single shot).

    The AR10 (308cal) is a pysically bigger receiver but I think the internal trigger system is interchangable between the AR15 and AR10 (???). The upper receiver, of course, has to be longer as well so that the bolt area will accept the longer fatter 308 cartridge. What is possible is the several roughly 25 caliber wildcat cartridges like the grendel (at least one other) but these are not yet readily available either for ammo or for conversions. There are 22LR conversions avaiable where it is an insert in the original barrel or a complete new upper receiver.

    Last edited: May 11, 2006
  5. lslubecki

    lslubecki New Member

    Mar 15, 2005
    Thanks for the reply. I never even thought about cartridge size. DUH! It all makes sence now.

    Steve Lubecki
  6. lslubecki

    lslubecki New Member

    Mar 15, 2005
    OOOO! Bolt on .50! My wallet feels lighter already.

    Steve Lubecki
  7. tankerman

    tankerman New Member

    May 13, 2006
    What kind of upper is it? If you can't find lower in your price range I may be interested in buying the upper
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