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Baga
06-07-2012, 12:32 PM
I'm sure this question has came up already, but if there is an UPDATED thread for this subject please let me know. If not, here is the questions...
I have a complete AR-15 .223 (5.56), I want to do an easy 9mm conversion.
Let's say I already have a complete CMMG dedicated 9mm upper. What other parts list do I need for the conversion to work (details, what company makes that part)? Do I have to change the hammer, some say yes & some say no? What 10 round 9mm mags are available?

hefedehefe
06-07-2012, 12:33 PM
:popcorn:

seainc
06-07-2012, 2:56 PM
get this http://www.gunbroker.com/Auction/ViewItem.aspx?Item=289978392

or this http://www.riflegear.com/p-631-cmmg-mk-9-dedicated-9mm-lower.aspx

9mm mag http://www.riflegear.com/c-53-9mm-magazines.aspx

9mm upper http://www.gunbroker.com/Auction/ViewItem.aspx?Item=289648246

hefedehefe
06-07-2012, 2:58 PM
get this http://www.gunbroker.com/Auction/ViewItem.aspx?Item=289978392

or this http://www.riflegear.com/p-631-cmmg-mk-9-dedicated-9mm-lower.aspx

9mm mag http://www.riflegear.com/c-53-9mm-magazines.aspx

Cant we use our 556 lower?

seainc
06-07-2012, 3:10 PM
Yes. you can use your 556 lower but parts specific to 9mm and your labor, I think it's better just get a dedicated 9mm lower. I have my CMMG 9mm carbine and I like it very much. Thanks

http://www.riflegear.com/c-143-9mm-lower-receiver-parts.aspx

crazychinaman
06-07-2012, 3:14 PM
I'm sure this question has came up already, but if there is an UPDATED thread for this subject please let me know. If not, here is the questions...
I have a complete AR-15 .223 (5.56), I want to do an easy 9mm conversion.
Let's say I already have a complete CMMG dedicated 9mm upper. What other parts list do I need for the conversion to work (details, what company makes that part)? Do I have to change the hammer, some say yes & some say no? What 10 round 9mm mags are available?

You can use your AR-15 lower.Cmmg does not need the 9mm hammer.You need a 9mm buffer,and the mag block .You have to use c/p mags ,uzi mags(converted for Ar-15)promags,and metalform mags and have them coverted to ten round mags.I think c/p makes ten rounders now.

that guy
06-07-2012, 3:32 PM
Cant we use our 556 lower?

Yes. But since your CMMG upper requires an ejector on the lower, you need to get a magwell adapter block with an integral ejector. What you are looking for is a magwell adapter block that has integral 9mm feed ramps, has an integral ejector, and accepts your 9mm magazines of choice. Bonus points if you have pre-2000 standard capacity magazines that will work.

They come in a few flavors, blocks that load into the top of the lower and can't be removed from the magwell, those that expand into the magwell, and those that use the standard AR-15 magazine release to stay put (I've used bullet buttons with these mag-wells to prevent muscle memory induced accidental adapter block release).

You can try these:

http://www.brownells.com/.aspx/pid=42515/Product/AR-15-M16-9mm-MAGAZINE-ADAPTER

http://www.brownells.com/.aspx/pid=24937/Product/AR-15-DEDICATED-9MM-CONVERSION-BLOCK

http://www.brownells.com/.aspx/pid=44736/Product/CAR-15-M4-9MM-MAGWELL-CONVERSION-BLOCK

You might notice that these seem difficult to bullet button. I'd go featureless if I were you. Depending on your bolt carrier, you may need a modified hammer. Also some recommend a heavier buffer and buffer spring, since 9mm ARs are blow-back, not gas impingement.


If didn't already have a colt style upper, you might also look at the olympic arms type upper that has an ejector built into the upper receiver. This gains you a little bit of width in the magwell, which can be used for wider sten mags, if you have old ones.

Let us know how it works out.