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another AR15/M16 question

Spartacus
a recent post about M16 parts got me wondering;
i have a pre-ban colt sporter in 9mm and a vietnam era complete upper (replacement barrel) in 5.56.
can i swap these uppers?
thanks
tom
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Comments

7 comments

Date Votes
  • mark christian
    If the pin sizes match up correctly you can swap uppers...Shooting the thing is another issue entirely.
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  • armilite
    If the pins don't exactly match up there is an offset bushing available through most AR-15 parts sellers. If you can't find one email me I should have a spare.
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  • quickmajik
    I'm not that familiar with Colt 9mm conversions, but wouldnt he have to also switch to a 5.56 hammer and buffer/spring, & bolt stop?


    Edit-
    I agree with Nwcid's second edit. there are newly made vintage looking A1 lowers on the market to boot, So you could have a gun that looks like an SP-1. Sarco sells a wide sellection of vintage A1 buttstocks with and without traps, slings and pistol grips.
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  • Nwcid
    The Colt lower has a pinned in 9mm mag block. You would have to remove the mag block to use the .223 mags.


    EDIT:
    quote:Originally posted by dcs shooters
    Also the hammer and buffer and spring would have to be changed.


    I guess the buffer would need changed. I would try and see it if works first, I will try mine tomorrow.

    Are you saying the hammer and hammer spring would need changed? Why? I know the Colt style 9mm AR's use a different width IIRC. IIRC the 9mm hammer will work on with the other calibers.

    My 9mm is an OA and it uses standard lower parts.



    EDIT 2:

    If this is a project you just want to do I say go for it. If you are just wanting to use your other upper I think you would be better served (and seems the general consensus) that you would be better off with a second lower. You can get new complete lowers for under $200 again.
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  • dcs shooters
    Nwcid has it right about the pinned in mag well blocks. Also the hammer and buffer and spring would have to be changed.
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  • Spartacus
    quote:Nwcid has it right about the pinned in mag well blocks.

    three roll pins, right?

    I'll compare the hammer and spring from both setups.
    the 9mm has no fwd assist. is that a function of DOM, or just not needed with 9mm?

    quote:.Shooting the thing is another issue entirely.

    something i don't know about?

    EDIT:
    quote:Posted - 03/25/2010 : 12:42:48 AM
    Hammer, magazine well, bolt carrier release, buffer and spring...Do you have these issues covered? At the very least; how are you going to get a .223 magazine to fit into a 9mm magazine well?


    i have all the parts, and then some. the mag well is sized down for the 9mm mags with removable blocks.
    quote:If this is a project you just want to do I say go for it. If you are just wanting to use your other upper I think you would be better served (and seems the general consensus) that you would be better off with a second lower. You can get new complete lowers for under $200 again.


    it's just one of those things that i think would work and wanted to try it. didn't know if i was missing something that would cause a catastrophic failure![:0][;)]
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  • mark christian
    Hammer, magazine well, bolt carrier release, buffer and spring...Do you have these issues covered? At the very least; how are you going to get a .223 magazine to fit into a 9mm magazine well?
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