CMMG vs JP vs MPX

[Tubadude]

I’ve been using my MP5 as my PCC for a while now, but the platform has its shortcomings, and it’s an SBR, so going to matches out of state is an ordeal, if possible at all.  

 

The three options I’m really looking at are CMMG, JP, and the MPX. The MPX really looks appealing, but people seem to be pretty split on it being awesome or terrible.  CMMG has an interesting bolt design, and JP seems to be a popular option. 

 

Any opinions on the trio?

[ABQautoxer]

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).

Edited May 7, 2019 by ABQautoxer

[assaultthesalt]

Don't forget to look at the MBX Extreme line of PCC's  

[SpaceMan]

JP always gets my vote

[Tubadude]

3 hours ago, assaultthesalt said:

Don't forget to look at the MBX Extreme line of PCC's  

I forgot about them.  Yeah, they're a consideration. 

 

I think the MPX is out and it's really down to JP, CMMG, and MBX. 

[JGT]

Definitely search for MemphisMechanic on the CMMG, he seems to have the most experience with that platform and has several great posts about it. The bolt system is innovative but ultimately I went with a standard AR9 for the huge aftermarket support and lack of proprietary parts.

 

I was making the same choice between CMMG/AR9/MPX and ended up with a Taccom complete upper on a QC10 lower. I have been very happy with it. Go look at the thread I started when I was making the decision and you can kind of see me work through it in real time in response to feedback.

 

I don't think you'll be unhappy with any of the 3 choices and at the end of the day what's needed is a ton of practice with the platform. I had expected PCC to be 'easy mode', but that is far from the case. There is a learning curve in terms of movement, positioning, and stage planning. Yeah you never (nearly never) have to reload and long shots are easier, but everything up close is slightly harder in my experience thus far. I think the biggest advantage of the PCC is when shooting while moving, so never stand still with a PCC if you can help it. Just my 2 cents based on my first few matches.

[Bwillis]

@bwikel What’s your cmmg experience. 

 

Mbx runs out of the box no issues good customer service 

 

jp I’ve never seen one in action

[Darqusoull13]

13 hours ago, Tubadude said:

I’ve been using my MP5 as my PCC for a while now, but the platform has its shortcomings, and it’s an SBR, so going to matches out of state is an ordeal, if possible at all.  

 

The three options I’m really looking at are CMMG, JP, and the MPX. The MPX really looks appealing, but people seem to be pretty split on it being awesome or terrible.  CMMG has an interesting bolt design, and JP seems to be a popular option. 

 

Any opinions on the trio?

I'm biased. My first GMR has 100,000 rounds on it. Now I'm think I'm up to 4 GMR's including the 15 with all the bells and whistles like the Short Stroke SCS and last round bolt hold open bolt. I've loaned out the GMR's to all sorts of shooters and they run regardless of the ammo, factory or reloads as long as they fit in a Glock mag they ship. JP's are popular because they are damn fine guns and they flat run. If you want a super light gun without the SBR hassle the new aluminum ultralight barrel might be right up your alley. 

Ping me if you need help building one in the rifle builder or one of those homie hookups 

 

12 hours ago, 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).

 

[Acer2428]

Use your search. This exact topic has been hashed and re-hashed and then over again.

 

I own, have shot/tested, and have competed with all 3 systems. (And several variants of the AR-9, but not a JP).

 

And I shoot an MPX SBR now. 

[bwikel]

4 hours ago, Bwillis said:

@bwikel What’s your cmmg experience. 

I put together a CMMG franken-guard in Dec. 2016 using a colt mag lower and side charging upper and I currently still run this set-up.  

 

The guard RDB system has advantages over the straight blow back system. The bolt opens at a lower pressure due to the delay, it runs a little cleaner than a blow back system and you don't have the inherent broken firing pin issue that most blow back actions have since it uses an AR firing pin. The buffer system can be tuned just like a blow back system so the dot movement and recoil can always be a little better than a blow back system. 

 

There were some minor challenges with the guard system out of the gate. Some owners have reported problems with extraction and CMMG replaced a few bolts and extractors. Personally the extraction issues I experienced were related to poor maintenance of my bolt where I had carbon build up behind my extractor hook and improper extractor tension. I resolved both by detail cleaning my bolt on a regular interval and replacing my standard extractor spring with an extra power version that I change annually now. The only other challenge I have run into was COAL of JHP's I loaded to run in my gun. The barrel has an extension just like a normal AR so it prefers pointed bullets such as round nose profile. I have been able to get JHP's to run by loading them shorter than I normally would for a pistol. Other than these issues and one mag extension problem my set-up has been extremely reliable.

 

If you wanted a guard  and don't like to tinker buy the complete carbine from CMMG. If you want to build your own guard based AR my recommendation would be to at least buy the CMMG bolt, barrel and guard lower. All the other parts you can pick your preference and they will work fine. 

[Texas45]

I have both....my story... injured my wrist so could no longer shoot pistols. Thought my shooting days were over and then PCC was  born. I bought a MPX GEN2.  Ran for the first 1000 rounds and then I couldn't get it to run, even after 2 trips to Sig.  Gave up bought the JP. It is heavier than the MPX but boy it RUNS.  Nothing better than to not have to worry if you gun is going to function. However my wrist was getting worse, I guess because of the weight of the JP and the NEW barrel and hand guard was not out yet for JP and SIG  came out with the Competition new and improved MPX sooo you guessed it....The MPX runs and runs BUT you have to clean piston and tabbet  every 1K or so. STILL worry about it not running. Ordering the new barrel and hand guard and short stroke system for my JP, why you might ask, I just LOVE that JP. Confused? Me Too. 

[seowitz]

22 hours ago, Texas45 said:

I have both....my story... injured my wrist so could no longer shoot pistols. Thought my shooting days were over and then PCC was  born. I bought a MPX GEN2.  Ran for the first 1000 rounds and then I couldn't get it to run, even after 2 trips to Sig.  Gave up bought the JP. It is heavier than the MPX but boy it RUNS.  Nothing better than to not have to worry if you gun is going to function. However my wrist was getting worse, I guess because of the weight of the JP and the NEW barrel and hand guard was not out yet for JP and SIG  came out with the Competition new and improved MPX sooo you guessed it....The MPX runs and runs BUT you have to clean piston and tabbet  every 1K or so. STILL worry about it not running. Ordering the new barrel and hand guard and short stroke system for my JP, why you might ask, I just LOVE that JP. Confused? Me Too. 

Yep, if you want a PCC you know will run all the time, every time, stop looking and get a JP GMR.  If you keep going back to your batshit crazy ex-girlfriend, then the MPX might be for you, cause damn when they run, they recoil like a airsoft gun!  But like your batshit crazy ex-girlfriend, you never know when it's going to throw a tantrum, and for how long......

[SergioSF]

8 hours ago, seowitz said:

Yep, if you want a PCC you know will run all the time, every time, stop looking and get a JP GMR.  If you keep going back to your batshit crazy ex-girlfriend, then the MPX might be for you, cause damn when they run, they recoil like a airsoft gun!  But like your batshit crazy ex-girlfriend, you never know when it's going to throw a tantrum, and for how long......

 

Truth profoundly spoken.

[Darqusoull13]

8 hours ago, seowitz said:

Yep, if you want a PCC you know will run all the time, every time, stop looking and get a JP GMR.  If you keep going back to your batshit crazy ex-girlfriend, then the MPX might be for you, cause damn when they run, they recoil like a airsoft gun!  But like your batshit crazy ex-girlfriend, you never know when it's going to throw a tantrum, and for how long......

This made my day. Thank you 

[Neomet]

10 hours ago, seowitz said:

Yep, if you want a PCC you know will run all the time, every time, stop looking and get a JP GMR.  If you keep going back to your batshit crazy ex-girlfriend, then the MPX might be for you, cause damn when they run, they recoil like a airsoft gun!  But like your batshit crazy ex-girlfriend, you never know when it's going to throw a tantrum, and for how long......

 

Thread winner!!  And thanks for reminding me of my ex-girlfriend.  Where did I leave her number.........

[mtruong]

I've run about 10,000 rounds through my MBX Extreme PCC, and while it's pretty good for the money out of the box, the recoil and construction causes the gun to break itself apart. It's been extremely accurate, and very well balanced, but over time the gun basically has torn itself to part. I've gone through 2 buffer tubes because the castle nut has ripped through the staking and shreded the buffer tube threads, and the front handguard has also stripped the barrel nut, and won't maintain a consistent position relative to the frame.

 

Once I shot my friend's Gen 3 MPX, I was sold. Very minimal dot movement, and the recoil is extremely soft, even with overpowered factory ammo running 150 pf. Follow-up shots and shooting on the move is much easier, and you can get away with much less technique with high accuracy. 

 

Reliability-wise, it depends on what generation you're running for the MPX. Talking to some of the top PCC shooters like Max Leograndis, Brian Nelson, and Zack Smith, the earlier Gen 1 and Gen 2 models were really hit or miss; I've got about 2000 rounds through my Gen 3, and it's been pretty outstanding. Even talked to Keith Garcia a little about it during the Safariland match, and he also swore by the MPX vs. JP GMR. 

 

Just my $0.02. 

[DocMedic]

I'm nearing the 1.5k mark on my MPX PCC gun. Gun is all factory with running Ball M882 ammo at matches, practices has been a mix of factory and 115gr reloads I had loaded from last year.  I want to get a little closer to 3k fired before I make judgement on this gun. But so far no Jams, issues or what have you's outside of running the gun dry without lube one time.

[Neomet]

Just an observation on the Gen 3 MPX reliability.  Remember that the issues with the first two gens didn't surface after thousands of rounds, they started right away and the first answer was to run hot ammo in them until they were broken in.  That does not seem to be the case here at all with the gen 3.  

 

[JAustin316]

JP!

[Shadyscott999]

If you go MPX, find a gen 1 and put a barrel in it from ILWT.  Mine are 100% reliable.  I sold my JP when I got the MPX.  

[Rotornut]

   I have decided to try out the PCC game, I was leaning towards MPX because of it's reputation for soft recoil. I wanted my wife to get into the game (USPSA, IDPA, steel, pistol shooter), and for her 5'2" 110lbs thought SIG might be the ticket. I held off due to many of the problems reported. Sig came out with the PCC model and I thought I'd give it a try.I took 500rds of factory ammo to the range when I picked it up, slapped a new Holosun green 510 on it, and proceeded to break it in.  I then took it home, cleaned and lubed it, and took it back to the range to try out some of my 147gr, 130PF pistol loads with it, HOLY COW is it soft. Round count is now at 1700, 2 USPSA and two steel matches, not a single hiccup.

  The only thing I've done to it besides clean it every 500rds, is put a TT magwell on, fits great. The adjustable stock it came with works just fine for both of us, just collapse it for her, and fully extended for me, the comb height is just fine with the massive Holosun window. The Timney trigger is great, even if just a little heavy at 4.5lbs. The trigger seemed to have a break in period also, it feels lighter now, but it could be my imagination as I get used to this thing, I haven't put a scale on it.

  We're still learning how to shoot PCC, but at our second steel match, which was carbine only, she took 6th and I took 4th out of 24 shooters. You don't use the word recoil with this thing, but "dot jump" as in, the dot doesn't jump out of the A zone at 15yds. My wife loves this thing and has become a PCC freak, I think I'm going to have to buy my own.

[Tubadude]

Thanks everyone.  I’m getting a JP.

[colt22man]

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.

[bwikel]

26 minutes ago, colt22man said:

I have one of each. 

I have broken firing pins in each.

I've never seen or heard of anyone breaking a firing pin on the CMMG Guard platform. You must be one of the rare outliers. 

[colt22man]

My CMMG is a 3 year old AR9 PCC.

Not entirely sure it is the guard platform.

However I experienced extractor retention roll pin issues and CMMG sent a new replacement bolt group with a new more robust firing pin