"Multi" caliber lowers..

Discussion in 'AR-15 Discussion' started by icallshotgun88, Jul 30, 2013.

  1. icallshotgun88

    icallshotgun88 New Member

    So I've been trying to find another thread to answer this for me but I haven't had any luck with a solid answer.
    So if I buy a lower marked "multi" for the caliber, can I build an AR 10 on that lower? Will it take the AR 10 magazines? And take the AR 10 complete upper, etc?
    Or do I need to buy an AR 10 lower receiver?
    I've built an AR 15 and wanted an AR 10. My LGS has "multi" caliber lowers and I want to know if I can use that for my build.
    I understand that I LEGALLY can build it with whatever caliber I want, but will it actually work the magazines, upper assembly, etc?
  2. MisterMcCool

    MisterMcCool Well-Known Member Supporter

    AR10 lowers are not the same size as Ar15. Multiple caliber uppers are available for either, but not compatible with both.

  3. Gatoragn

    Gatoragn Active Member

    The AR 10 is not interchangeable with AR15. The mag well is larger for one thing, therefore overall longer and wider. The multi caliber on AR15 means you can assemble various calibers, 5.56x45, 6.8 spc, 300 blk, 6.5 Grendel, 7.62x39 and a few more, on your stripped lower, the manufacturer did/does not how the customer will use the product.

    You can also use.5.56 stripped lower for various builds, just not a 308 win or 6.5 Creedmore.
  4. c3shooter

    c3shooter Administrator Staff Member

    Besides the mag well being different size, the buffer is different on a .308 sized rifle and a 5.56 sized rifle. The upper itself has different dimensions, so you can't mix/match.