CMMG vs JP vs MPX

[Chris Keen]

I understand everyone is different, and there will always be anomalies among different platforms, but I've never NOT seen an MPX run well. I've been shooting an MPX Gen2 for going on 3 years, and it's been flawless. I run 135 PF reloads with CMJ type bullets, and mixed range brass. No issues as long as you keep it clean, which isn't really any harder than a standard AR to clean. And replace the mag springs once or twice a year.

 

Last year at the JP AREA 5 match I was squadded with Todd Jarrett and we were both running MPXs.  Lots of other shooters had at least 1 or 2 jams at some point during the match, but not our MPXs. Flawless.

 

Long story short, Todd won the whole match & I came in 3rd right behind Max Leograndis. 

 

[Tampa-XD45]

12 hours ago, colt22man said:

I have one of each. All function nearly flawlessly. All have different recoil impulses. The Sig MPX gen 2 has the softest recoil of the 3.

The MPX is also the most time consuming to clean. I remove the barrel & clean the gas block body and piston every 500-700 rounds.

I have broken firing pins in each. I have spare firing pins and replace them every 5000 rounds.

You will enjoy shooting your PCC immensely what ever your choice.

Your welcome to join us at the JP Enterprises Midwest PCC Championship to be held @ Silver Creek Conservation Club Sellersburg, Indiana Memorial Day weekend 2019.

Since you have one of each, other than firing pins, how would you compare reliability?

[Chillywig]

12 hours ago, Chris Keen said:

I understand everyone is different, and there will always be anomalies among different platforms, but I've never NOT seen an MPX run well. I've been shooting an MPX Gen2 for going on 3 years, and it's been flawless. I run 135 PF reloads with CMJ type bullets, and mixed range brass. No issues as long as you keep it clean, which isn't really any harder than a standard AR to clean. And replace the mag springs once or twice a year.

 

Last year at the JP AREA 5 match I was squadded with Todd Jarrett and we were both running MPXs.  Lots of other shooters had at least 1 or 2 jams at some point during the match, but not our MPXs. Flawless.

 

Long story short, Todd won the whole match & I came in 3rd right behind Max Leograndis. 

 

My Gen 2 MPX has been extremely reliable. I think the secret is cleaning and cleaning often. I just preventatively put new rings on the tappet and gas plug,  changed the firing pin and extractor and recoil springs. I'm at about 10k

 

Chris what does your cleaning and gas system maintenance schedule look like? 

[Chris Keen]

Looks allot like yours, except I only shoot PCC one or two matches a year, so I haven't replaced my rings or my firing pin yet. I had a firing pin break last year and Sig replaced it at no cost. 

 

I do clean it after every practice or local/major match, and I always clean the gas valve & tappet.  So yeah I think keeping it clean is a big part of making it run reliably. 

Edited May 23, 2019 by Chris Keen

[Jack04]

On 5/6/2019 at 10:08 PM, ABQautoxer said:

You will get fans of each to respond. I'll try to be as neutral as possible with the two I have experience with. My two JPs just run and can outshoot me. We had a PCC bowling pin match and everyone lost at least one round due to a malfunction of some kind each except for two, you guessed it, our two GMR-15s. The MPX shoots softer, I'm not convinced the dot moves any less than my short stroked JP but it certainly feel just very easy to shoot. I liked it and was the first PCC I was going to buy until I started to read and then was told how unreliable some have been. Our local GM had so many issues he gave up and got a JP. So while they aren't the cheapest, you can get a discount code from a JP team shooter (some on here or I can put you in touch with one) that is not an insignificant discount. I have no regrets spending the money and would recommend both the rifle and the excellent customer support I got when I wanted to buy accessories, a second rifle, and short stroke one. I will be ordering their fancy new lightweight barrel which likely won't make me any more competitive but I might enjoy it even more.

 

I've never shot the CMMG, I love the design though. Several people here have experience with them and I think several like Memphis have modified them (or their action).

Do you happen to have a discount code for the JP as mentioned. getting close to having the 2G saved and a discount would make it happen that much sooner.

Thanks for your time

 

[Bifurcate]

Got to shoot all three the JP GMR, MPX, and CMMG RDB this weekend.

 

Its not even close.

 

I was EXTREMELY disappointed in the JP. It's snappy because it's blowback, but clearly more recoil. It's a 1994 Rock River 9mm, literally identical makeup. I had faster splits with delayed blowback. But hey.... Keep buying the JP! Makes my chances better if I'm shooting against you

 

I'm impressed with JP's marketing, getting lines of people to spend about double the value on blowback AR.

 

Don't take my word for it at all. COMPARE before you buy.

Edited June 13, 2019 by Bifurcate

[colt22man]

On ‎5‎/‎22‎/‎2019 at 9:41 AM, Tampa-XD45 said:

Since you have one of each, other than firing pins, how would you compare reliability?

I've been helping with (2) level 2 USPSA major match's at our club in the last 4 weeks. I've been buried. Sorry for the late response. I would rate reliability equal on all 3.

My only other failure was a extractor roll pin in my CMMG fell out during a match. I had removed it from the bolt for cleaning the extractor. It went in back in all to easy. Should have been paying closer attention. More of a self induced problem than a design problem. I love shooting all three. I would recommend all.      

[Bifurcate]

21 minutes ago, colt22man said:

I've been helping with (2) level 2 USPSA major match's at our club in the last 4 weeks. I've been buried. Sorry for the late response. I would rate reliability equal on all 3.

My only other failure was a extractor roll pin in my CMMG fell out during a match. I had removed it from the bolt for cleaning the extractor. It went in back in all to easy. Should have been paying closer attention. More of a self induced problem than a design problem. I love shooting all three. I would recommend all.      

 

You think it was a bad roll pin? What would you have done differently noticing it went back in too easily?

[colt22man]

I know have new roll pins. When I drive the old one out to clean the extractor I install a new roll pin.

[rowdyb]

I just sold my pos MPX that has plagued me from day one with issues. I hate that gun.

[Darqusoull13]

12 hours ago, rowdyb said:

I just sold my pos MPX that has plagued me from day one with issues. I hate that gun.

Hey Rowdy, is it time? 

[Fasthenk65]

6 hours ago, Darqusoull13 said:

Hey Rowdy, is it time? 

wtf Rowdy please explain!

 

[rowdyb]

2 hours ago, Fasthenk65 said:

wtf Rowdy please explain!

 

i wanted to run the exact same ammo i use in my pistols on Production for my mpx in PCC with zero changes. trying to do this for the past year and half has resulted in me never having a gun that functioned 100%. it didn't matter bullet profile, length, or powder. it didn't matter clean or dirty. dry or lubed. it didn't matter everything stock or totally  modified. NOTHING ever gave me a gun that could shoot even 100 rounds without something wrong. taccom parts, stock parts or ilwt parts, didn't matter. (though robert and i talked on the phone hours and hours over weeks trying to resolve it. including about 4 shipments of parts back and forth. though i never did just send the whole thing to him)

 

i constantly had feeding errors off the right side of the magazine and ever present failures to extract.

 

PLEASE PLEASE PLEASE do not tell me what worked for you and what I should do differently. the gun is sold and gone.

[rowdyb]

hear my wailing and gnashing of teeth that was the final straw

 

[Aircooled6racer]

Hello: Well, since you sold it just move on to your next PCC. Get one and don't mess with it until you have shot at least 2000 rounds through it. I have seen way too many people try the next best thing to their brand new PCC and mess it up. If it doesn't run right from the start send it back to the builder. Don't try to make it better unless you know what is causing the problem and how to fix it. This is not directed to you but to everyone who is starting the PCC game or even any gun game. All guns will fail at some point since they are a mechanical device that wears. Is there one PCC better than the rest, not really but one that runs 100% is better than ones that don't. Thanks, Eric

[Neomet]

6 hours ago, rowdyb said:

hear my wailing and gnashing of teeth that was the final straw

 

 

This is like when I am sitting watching a horror movie but rather than yelling at the screen "Don't open that door!" I'm yelling "Don't rack it without dropping the mag!"  As a member of the club I get your pain.

[rowdyb]

Yep I just made it worse. But I also shouldn't have to do it. 

[Neomet]

Oh, I totally, totally agree.  I will also confess that more times than not I have done exactly the same thing.   Racked the bolt and gave myself death jams that are almost impossible to clear without tools.  Quick way to ruin a whole day at the range with friends.      

[SergioSF]

I actually wore out my Radian Raptor charging handles from a season's worth of clearing malfunctions! 

(yes, on both MPXs)

 

[Fasthenk65]

16 hours ago, rowdyb said:

i wanted to run the exact same ammo i use in my pistols on Production for my mpx in PCC with zero changes. trying to do this for the past year and half has resulted in me never having a gun that functioned 100%. it didn't matter bullet profile, length, or powder. it didn't matter clean or dirty. dry or lubed. it didn't matter everything stock or totally  modified. NOTHING ever gave me a gun that could shoot even 100 rounds without something wrong. taccom parts, stock parts or ilwt parts, didn't matter. (though robert and i talked on the phone hours and hours over weeks trying to resolve it. including about 4 shipments of parts back and forth. though i never did just send the whole thing to him)

 

i constantly had feeding errors off the right side of the magazine and ever present failures to extract.

 

PLEASE PLEASE PLEASE do not tell me what worked for you and what I should do differently. the gun is sold and gone.

 

Pfff my MPX is nearly here... hope I have more luck. What's next Rowdy> A JP?

[Neomet]

Henk, I would consider the PCC version significantly enough different to not look at issues with prior versions.  Not saying everything is peaches and cream yet as round counts are still relatively low but I have seen no posts here or elsewhere discussing the typical MPX feeding/ejection issues on the PCC model.  Just my observation.      

[Fasthenk65]

3 hours ago, Neomet said:

Henk, I would consider the PCC version significantly enough different to not look at issues with prior versions.  Not saying everything is peaches and cream yet as round counts are still relatively low but I have seen no posts here or elsewhere discussing the typical MPX feeding/ejection issues on the PCC model.  Just my observation.      

Tnx... you noticed I am a bit nervous  Had a chance to shoot gen 2 at CZ Extreme Euro Open and really really loved the gun, amazing. fast hits at a plate at 30 yards.... I have 2 coming in (a sig and a JP) best one stays ... quite some money.... enjoy it all too much. Tnx!!

[Neomet]

  

Ahhh, the joys of anticipation!