Glock mag compatible M4 lower

[Grizzly21]

ISO...Glock mag compatible M4 lower & complete upper in 9mm

What brands are available, pros & cons?

Where to purchase.

[LtDave]

I recently bought a JP Enterprises GMR-13 rifle and so far I'm very pleased. Got it off Gunbroker. Initial zero at 20 yards with an Aimpoint H1 red dot resulted in a number of .5" to .75" groups. One stovepipe initially with some Aguila 124 FMJ that seemed a little low pressure (lots of soot on the empties). A bunch of other 9mm factory and handloads all ran fine. Used the supplied Glock G26 mag and a 21 round Magpul one. No drama there. Trigger is quite nice. The 20 yard zero works out to be under 2" plus/minus POA/POI from 0 to 95 yards with either 115 or 125 grain loads.

[voodoo_man]

quarter circle 10 seems to be the top of the line type of thing...

Angstadt Arms UDP 9 and Law Tactical 3-M Folding Adapter seem to be a good popular combination...

ETS group 31 round mags work well in this context, and they are clear so there that.

However, I'd highly recommend going to a purpose built 9mm type gun, specifically an mp5 type of setup.

Experience note/consideration: I have shooting buddy's who have 9mm AR15s, they are cool and all, but even as a pistol config you are still only shooting 9mm from a rifle...which a pistol can do just as well. Seeing as how you can build an 8" 300blk or get an AK pistol in the same size range, it is sorta counter-productive to consider a 9mm AR a good defensive tool. If you are looking for it to be a supplement to your training in an AR platform, then awesome, go for it.

[SD]

Wilson Combat AR9GAttachment 10906

[SteveB]

I recently bought a JP Enterprises GMR-13 rifle and so far I'm very pleased. Got it off Gunbroker. Initial zero at 20 yards with an Aimpoint H1 red dot resulted in a number of .5" to .75" groups. One stovepipe initially with some Aguila 124 FMJ that seemed a little low pressure (lots of soot on the empties). A bunch of other 9mm factory and handloads all ran fine. Used the supplied Glock G26 mag and a 21 round Magpul one. No drama there. Trigger is quite nice. The 20 yard zero works out to be under 2" plus/minus POA/POI from 0 to 95 yards with either 115 or 125 grain loads.

Same story for me on the GMR-13; very accurate and no malfunctions yet. Excellent trigger. RMR on an ADM mount, Federal 147 gr AE. Just wish the bolt would lock back on an empty mag.

[LtDave]

Yes, not locking open on the last shot is about the only downside so far on the JP. Just installed a Millet DMS-1 1-4x on mine and will try it at 50 and 100 soon.