MPX 9mm Carbine or Something Else?

[Vegas]

Hey all,

I am looking at picking up an MPX PCC, gen 3, and was wondering if there is anything else out there that I am missing in the $1500-1700 range? Requirements are reliability, bolt lock back, 9mm, 16” barrel and probably not blow back.

Thanks for any input in advance.

Cheers.

[JoshNC]

I say this as someone who historically hates the Colt M16/AR15 9mm. The CMMG radially delayed blowback is awesome. We have an upper set up with a 9” barrel, 3-lug adapter, and Mega wedge lock rail on one of our M16 lowers using the Mean Endomag. This setup is fantastic. Very smooth shooting, far more so than a standard blowback AR/9 and comparable to our MP5s. If a 16” barrel is a necessity for you, I would personally choose the CMMG RDBB over any MPX offering. You can order the barrel and bolt group, then set it up as you please.

[Hkbeltfed]

JoshNC, what buffer and action spring are you using? Also, are you using their bolt weight kit?

[SteyrAUG]

I say this as someone who historically hates the Colt M16/AR15 9mm. The CMMG radially delayed blowback is awesome. We have an upper set up with a 9” barrel, 3-lug adapter, and Mega wedge lock rail on one of our M16 lowers using the Mean Endomag. This setup is fantastic. Very smooth shooting, far more so than a standard blowback AR/9 and comparable to our MP5s. If a 16” barrel is a necessity for you, I would personally choose the CMMG RDBB over any MPX offering. You can order the barrel and bolt group, then set it up as you please.

I didn't even know that was a thing. Is that standard on all CMMG 9mm stock ARs?

[1168]

I didn't even know that was a thing. Is that standard on all CMMG 9mm stock ARs?

No. Their Colt mag models are straight blowback. Their “Guard” or “MkG” Glock mag models have the radial delayed blowback.

[Vegas]

I say this as someone who historically hates the Colt M16/AR15 9mm. The CMMG radially delayed blowback is awesome. We have an upper set up with a 9” barrel, 3-lug adapter, and Mega wedge lock rail on one of our M16 lowers using the Mean Endomag. This setup is fantastic. Very smooth shooting, far more so than a standard blowback AR/9 and comparable to our MP5s. If a 16” barrel is a necessity for you, I would personally choose the CMMG RDBB over any MPX offering. You can order the barrel and bolt group, then set it up as you please.

Thanks for the response. Sounds like something that would work but I don’t really feel like building this time around. Sometimes it’s nice to buy something off the shelf. I watched a few YouTube videos on the Guard and one thing that caught my eye was their ARC magazine. Made me think about using a shorter upper with my standard SBR lower.

Given my research, I think it’s likely I’ll get the MPX as I have actually shot that and know what I’m buying.

[JoshNC]

BCM A5, standard rifle spring, A5H3 buffer. It’s great.

[SteyrAUG]

No. Their Colt mag models are straight blowback. Their “Guard” or “MkG” Glock mag models have the radial delayed blowback.

Ok, thanks.

[HardToHandle]

Respectfully, the MPX seems a fading platform. keyMod in the MLOK era, unfortunately denied extended baffle, and the magazine debacle killed the MPX momentum at the emergence of the PCC popularity. It seemed to have the trigger modularity, bolt hold open, ergonomics and many items working in its favor. Had SIG invested in reasonable R&D, maybe it would have soared. I looked seriously at the MPX early in the initial release, by happy that I passed.

I have been running 9mm blowback ARs for years. I finally got an MP5 clone earlier this year. Night and day difference. If you want a solid BHO, don’t settle for a blowback gun.

[Vegas]

Respectfully, the MPX seems a fading platform. keyMod in the MLOK era, unfortunately denied extended baffle, and the magazine debacle killed the MPX momentum at the emergence of the PCC popularity. It seemed to have the trigger modularity, bolt hold open, ergonomics and many items working in its favor. Had SIG invested in reasonable R&D, maybe it would have soared. I looked seriously at the MPX early in the initial release, by happy that I passed.

I have been running 9mm blowback ARs for years. I finally got an MP5 clone earlier this year. Night and day difference. If you want a solid BHO, don’t settle for a blowback gun.

Any experience of the Gen 3 MPX?