CMMG AR 9 lower

[oldfatguy]

CMMG has announced a new 9 mm MKGs lower that uses Colt pattern mags. However it is only compatible with 9 Luger marked barrels, not 9x19 barrels. Anyone know what is different?

OFG

 

[Laseredge]

My CMMG rotary locked 9mm barrel is marked 9X19, the 9mm Luger barrels must be the Glock/Colt straight blowback barrels.

 

[oldfatguy]

My CMMG rotary locked 9mm barrel is marked 9X19, the 9mm Luger barrels must be the Glock/Colt straight blowback barrels.

My MK9 (blow back) Colt mags barrel is marked 9x19 NATO, just like the RDB barrel.

OFG

 

[Downtown]

What possible difference could there be?

 

[oldfatguy]

What possible difference could there be?

Exactly my question.

OFG

 

[kl3309]

Lower Receivers

Looking for an AR15 lower receiver or lower receiver assembly? CMMG has you covered with all things lower receivers.

cmmg.com

Bottom of the above page says, "CMMG has made a small modification to 9mm barrels in order for them to be compatible with Mk9 lower receivers. This modification only applies to Mk9 platform lower receivers and does not positively or negatively affect functionality of the barrel with a MkGs, Mk4 or Mk17 platform lower receiver. Barrels that are stamped “9mm Luger” will be compatible with an upgraded Mk9 lower receiver. If your barrel is marked “9x19 NATO”, you will need to purchase a new 9mm barrel in order to ensure reliable function."

The new lower is a new configuration that uses Colt SMG mags with a modified CMMG RDB bolt and barrel. The new lower deletes the ejector and has modified a bolt catch and feed ramps. CMMG's website also lists conversion kits for existing SMG mag blowback lowers to go to the new SMG mag RDB configuration (with different kits for ASC mags and Colt/Metalform mags).

Parts Kit, Mk9, 9mm Radial Delayed Blowback™, ASC/CPD Mags | CMMG - AR 15 and AR 10 Builds and Parts

BUFFER SPRING: Carbine BUFFER: Carbine MAG RELEASE: Mk9 BOLT CATCH: Mk9 FEED RAMP: ASC/CPD Mag Optimized CMMG has

cmmg.com

Parts Kit, Mk9, 9mm Radial Delayed Blowback™, Colt/ Metalform Mags | CMMG - AR 15 and AR 10 Builds and Parts

cmmg.com