9mm assembly - parts experience/reviews

hv55maxx

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Got the stamp for SBR in 556 and want to pursue a 9mm set up for my next toy. looking for any reviews or experience with any the parts i'm thinking of using.

mag well adapter - uzi mags to be modified since they are cheap

------I have considered the Macon Armory one as well, but price difference and i've had good experience using KAK parts before leans me towards KAK
------ 9mm Colt Pattern Magazine Well Adapter


dont want to deal with different brands (or headspacing) so just going to get a complete upper (side charger is cute)


any input on buffers/springs/barrel lengths (4.5" i might as well buy another handgun - so 7"+ preferably) etc would be appreciated as well.
thanks in advance.
 
8-10" is ideal for 9mm ballistics, and will provide adequate rail space to hold onto.

The Hahn precision top load is the best conversion block available, it is the design all others are copies of.

You will want a total reciprocating weight of about 20oz, and a heavy spring. A 308/ar10 carbine spring and the spikes st9x is a good setup, better yet is the kynshot/blitzkrieg hydraulic buffer. Both of these buffers will reduce the overall travel of the bolt, you can further reduce the travel with 25cent US coins in the back of the receiver extension.
 
I tried a magwell adapter......very unreliable.

I went with a CMMG 9mm lower with a PSA 8 inch upper. It runs absolutely flawlessly.
 
These work great. Just put 9mm upper on your 556 lower. These mags have a 9mm insert.

 
can you elaborate on the reliability issue?

I tried a magwell adapter designed for Colt style mags and there was ridiculous feeding issues. The feed ramp sat too low and just wouldn't feed correctly.
I couldn't get four consecutive shots without a misfeed so I ordered a CMMG 9mm lower and threw a parts kit into it, put my 9mm upper on it and haven't had any misfeeds. It cycles perfectly as fast as I can pull the trigger whether using hollow points or ball.
So far I've got about 1500 rds through it, slow fire and rapid fire without any malfunctions. The last round bolt hold open also works, the mags drop free and I can used modified Uzi mags in it by milling the mag catch hole and still use them in my Uzis.
I recommend the 9mm CMMG lower highly.
 
I tried a magwell adapter designed for Colt style mags and there was ridiculous feeding issues. The feed ramp sat too low and just wouldn't feed correctly.
I couldn't get four consecutive shots without a misfeed so I ordered a CMMG 9mm lower and threw a parts kit into it, put my 9mm upper on it and haven't had any misfeeds. It cycles perfectly as fast as I can pull the trigger whether using hollow points or ball.
So far I've got about 1500 rds through it, slow fire and rapid fire without any malfunctions. The last round bolt hold open also works, the mags drop free and I can used modified Uzi mags in it by milling the mag catch hole and still use them in my Uzis.
I recommend the 9mm CMMG lower highly.

do you remember the brand you used?
 
So far I've got about 1500 rds through it, slow fire and rapid fire without any malfunctions.

I have an estimated 40-50 thousand rounds through my 9mm AR, With above mentioned Hahn precision block, it has won 2 USPSA Area championships and a top 10 at Nationals. Not saying the carbine has been 100% reliable throughout that whole time, but I can not think of a time where a problem was caused by my conversion block. Hahn
 
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