AR-9 build.

[Ggreen]

Unfortunately I dont have any experience with normal blowback AR 9 uppers or P80 lowers. CMMG may be able to help. They may end up recommending their lower, but it doesnt hurt to ask. The CMMG uppers are nice because the radial delay blowback softens recoil and lowers port pop if you are planning to shoot suppressed. The Juggernaut lower will supposedly work with CMMG uppers if you do some machining on the bolt catch to adjust the magazine height. If you dont mind doing that gunsmithing work, you could probably make your combination functional.

Not all cmmg 9mm uppers are rdb from what I'm seeing

 

[sloppyjoe]

Not all cmmg 9mm uppers are rdb from what I'm seeing

Do you have a link? When I go to CMMGs website and filter on complete uppers in 9mm, they all say RDB.

 

[Ggreen]

Does look like all the current production is rdb guess they went all in. From the videos they look to be mil spec compatible though

 

[t-squared]

I recently bought one of Foxtrot Mike's 16" uppers and love it.

I'm using the EndoMag conversions in a regular PSA lower. Following their guidelines I replaced the buffer with their 6.4oz one and the spring with a 308 carbine one. The gun ran just fine with a 5.4oz "H-3" also. The only other change was to replace the hammer spring with a reduced rate one from the JP Enterprises kit....I'm not using SRPs and the standard spring, while not piercing the spp primer cup, was still making a very deep indent.

The setup had been 100% through it's first 300 or so rounds and as an added bonus it eats flat point bullets from Precision and J-Ames without a hitch.

Foxtrot Mike products

 

[Gd999]

Not all cmmg 9mm uppers are rdb from what I'm seeing

When I emailed their support they said only their uppers will work with their lowers, and that they use a proprietary system.

 

[Gd999]

I was able to put a full kit together from about five different places. Got an 80% lower from gunbroker. Good brand. No one else has 80% in stock. Got a Foxtrot Mike 8.5” upper. Found a lower parts kit from optics planet. Grabbed a bunch of Glock 32 round mags. Decided to go with a 9mm pcc trigger from cmc. Supposedly the 9mm ar is really tough on triggers and this one can handle it. Brownells had the rest in stock. I got the special spring and buffer. I already have a pistol brace. I’ll probably add an aim point pro sight and maybe some type of front grip. Also a single point sling. Not sure if I should add mbus flip up sights or not. I’m pretty excited about this gun.

 

[Gd999]

I recently bought one of Foxtrot Mike's 16" uppers and love it.

I'm using the EndoMag conversions in a regular PSA lower. Following their guidelines I replaced the buffer with their 6.4oz one and the spring with a 308 carbine one. The gun ran just fine with a 5.4oz "H-3" also. The only other change was to replace the hammer spring with a reduced rate one from the JP Enterprises kit....I'm not using SRPs and the standard spring, while not piercing the spp primer cup, was still making a very deep indent.

The setup had been 100% through it's first 300 or so rounds and as an added bonus it eats flat point bullets from Precision and J-Ames without a hitch.

Foxtrot Mike products

I’ve heard nothing but good things about foxtrot. Reddit recommended him. I was able to grab one of the few uppers he had left. Primary arms carried the two styles he had left. One was a 7” barrel for $315 or a 8.5” barrel for $390. I went with the second one. Just glad I found one.

 

[stack23]

I have a spikes tactical dedicated 9mm lower that has been flawless. The key is a heavy 9mm buffer and a 308 spring, it runs like a top and the lrbho works everytime

 

[bwframe]

If you really want to test your AR9 for actual reliability, you need to run it in a few USPSA or Steel matches, in the heat of summer. That will separate the wheat from the chaff.

Lotta guns are "100% reliable," then they find out the hard way. Much better to do this than find out in an expensive carbine class that you are carrying a good club.