NervousEnergy

This 100%. I've got both a Gen 2 and a Gen 3. The Gen 2 was great for me, but it took a fair bit of money on top of the purchase price. Trigger, ILWT barrel & handguard, etc. The Gen 3 is stock other than a magwell, and has run flawlessly for over 7000 rounds with only standard maintenance. Took a class this last weekend with Max L and after all of us put 2000+ rounds down range over 2 days my Gen 3 was the only gun without a single flaw. I clean everything but the gas system every other match (around 400-500 rounds), and the gas piston every 1000 just like on the Gen 2. I did *not* clean the gas system Saturday night after the first day of class and the gun still ran flawlessly the next day, so I may get lazy and push that out to 2000 rounds. It only takes a minute to dismount the barrel and pull the piston out, but I'm fundamentally lazy. It is annoying that the first two generations had issues, but at least they did finally put out a version that's a great competition gun right out of the box. The 4.5 lb Timney doesn't give as fast a split as the Hiperfire Eclipse in my gen 2 (16ms vs 12ms), but I'm nowhere near good enough as an A shooter to really take advantage of that.

The Springer seems to work well, though I've never done anything as rigorous as a time study to see if there's a measurable improvement in average reload time. I don't practice reloads nearly as much as I should - not having to perform reloads in the #1 reason I went PCC. There's already a bit of slope in the front. The muzzle device is the MBX. Not sure if it's effective because it ever so scientifically vents gas upwards, or because it's a piece of metal on the end of the barrel, but it does work. I don't get any more or less dot bounce on the Gen 3 with the stock device, though. I shoot left handed so the Odin releases are critical for the big left side paddle. Works perfectly.

Not the extractor - that spring is tiny compared to this (less than half the size) and it's still in place. I've broken the extractor spring twice on my gen 2 - they seem to die every 5000 - 6000 rounds, and the hiperfire disconnector dies around 8000. This Gen 3 has maybe 4000 on it. It could be the disconnector, but the trigger is resetting fine in dry fire. The one time the disconnector spring broke on the gen 2 it broke in half (Eclipse), but stayed in the trigger housing. I was going to take it to the match tomorrow to test it but shoot the backup Gen 2, but it's cancelled due to rain. That will give me time to remove the Timney and see if most of the disconnector managed to escape (can't see it directly due to the hammer bridge). If that's not it I don't know where else to look - perhaps take apart the safety and see if the detent spring is missing. Safety feels exactly the same, though. Really annoying that I can't seem to find a full exploded view of every part in the MPX Gen 3. Is there such a thing? The only pictures I can find of the Timney is the gold version, which isn't exactly the same as this black one that come stock. I'll check the bolt catch spring, but the bolt catch lever seems to have exactly the same tension on it. Thanks for the ideas! I'm used to a few parts left over after major car work, but not guns.

Curious why folks say the gold 3.5 lb Timney isn't for the MPX - the only thing differentiating an 'MPX' trigger from any other AR trigger is the hammer bridge to soak up some of the abuse, and the gold one comes with one just like the heavier pull black one. I've got a Gen 2 with an Eclipse and a Gen 3 'PCC' (I wish they would have just officially called it a Gen 3) with the stock Timney. Can't tell the difference on the clock. The Hiperfire has around 12K rounds through it. The disconnector spring broke at 7K - 5 minute fix. Recommend getting a dozen springs (they cost virtually nothing) and replacing every 3K for peace of mind.

Nope, firing pin spring is larger than this one and is accounted for.

Embarrassing topic, but I'm not used to unidentified parts coming out of my guns. Have an MPX PCC (the 'gen 3' model) and a gen 2 for backup. Took it apart today to clean it after yesterday's match as I've done many dozens of times, but a small spring came out of the lower when I separated the upper. I've not paid a lot of attention to the lower with it's Timney trigger - I can't hardly tell any difference between it and the Hiperfire in my Gen 2. I just swab out the old sear grease around the disconnector and hammer and put some new grease in. I haven't removed the trigger or paid much attention to it, so if this spring came from there I don't know where it goes. Can't find any exploded parts diagrams of the Timney or the MPX lower itself - my google-fu is failing me. It looks way too big to be the Timney disconnector spring, and I have no idea how it would have gotten out of there intact. Spring doesn't look broken. Picture attached with 9mm round for sizing. Part of the safety? Safety seems to work fine. Dry fire function check is perfect, but there's no way I'm taking this to a match with an unidentified spring missing. I don't even want to fire it at a range without knowing what it is. Once again, embarrassing question, but does anyone have a clue where this goes?

I've got both a gen 2 with a ton of mods (Eclipse, ILWT 14.5, etc.) and a Gen 3 will almost no mods. I can feel the difference between the Timney and the Eclipse, but it makes zero difference in run times. I'm faster with the gen 3 on most USPSA courses with all double-taps and medium-range targets, and faster with the lighter gen 2 in Steel Challenge. Very subtle, though. Both run great. The gen 2 has close to 20K rounds through it so got the PCC as a 'backup' and, of course, it took over as primary. At $1300 it's a good deal, but depends on how wedded you are to Hiperfire and how much you can get it for. I got my gen 3 for $1608 from Grab a Gun last February, so new comp and trigger just about equals out that cost if you don't get the Eclipse on sale or go for a cheaper model. Can't stand the bird cage, though it really doesn't make any performance difference.

DFW - Dallas/Ft. Worth. I wouldn't be interested in flying to a class, though the 5 day pistol or PCC camp at TPC in Utah is tempting. Driving 5-6 hours to North Texas, OK, West Arkansas, etc wouldn't be out of the question, though I'd of course prefer a local option. We have three national caliber ranges in DFW and dozens of smaller sites, and a huge action shooting customer base. Getting a dozen people to pay $400-$500 for a 2 day course would be as simple as announcing it. Racaza, Stoeger, etc. regularly sell out every course they do here. Teaching optimal movement is the thread topic and probably the biggest need.

If it's not competition specific, then what's the point? I've checked out every carbine/rifle class in the DFW area, and called several. They're all about warfighting with a rifle. Concealing your position, engaging at range while using cover, covering teammates advances. I'm not taking any class where plate carriers are strongly recommended. This is a game of tenths or hundredths of a second. The top pistol instructors are examining your entry and exit from firing positions, your footwork, transition speed, stage planning, and a bunch of other factors that collectively will push you from also-ran to the next level up. These skills can certainly have applications in the real tactical environments the rile classes around here purport to teach, but unless you're going to the John Wick school of close combat they're certainly not going to be emphasized. There's a bunch of people out here yelling 'take my money'. Someone just needs to step up and take it.

I've got ~11000 on my Gen 2. Extractor spring failed around ~7500 rounds... found out it's recommend to replace it at 5000, so my bad. They cost a buck each or so with the plastic insert from Taccom. Disconnector spring failed in the Hiperfire Eclipse at ~10,000. Replaced it with the unused spring in the OEM trigger. So far only around 600 rounds on the Gen 3. Broke it in & sighted it with 200 rounds, then shot it in the Silver Dollar match (12 stages, one day, no cleaning.) Ran perfectly. Not a high round count, of course, but there are numerous improvements in the design. My Gen 2 threw brass shavings into the upper and lower for the first 5000 rounds or so. Never an issue feeding, but it seems for many Gen 2 MPXs the left side feed ramp wasn't smooth or slightly misaligned. No such issue with the Gen 3. The new slide-in action of the spring assembly is really nice for cleaning. The new handguard is a dream, and the Timney is so close to the Hiperfire that I'm not switching it out. The extractor spring appears heavier duty with a thick O-Ring at the base. The only thing on the gen 3 that disappoints me is the charging handle. The tongue on the spring retainer keeps the upper from getting scuffed at the back, but doesn't do anything to keep the handle solidly in the grove and prevent binding. The NL spring retainer ($40) is at least required, and getting the whole package will get you much wider handles.

This is an area where I really wish a few top instructors would get in the PCC class game. There are multiple opportunities here in DFW every year to take competition pistol classes from the best in the business, where you can really commit the time to figuring out (with an expert helping you) things like shooting positions, movement, stage approach, etc. I've taken one and it was worth every penny and then some (Ben Stoeger). A 2 day PCC class of the same quality as what Stoeger, Racaza, etc. offer for pistol would sell out in minutes here.

It's a piston gas gun, so it loves heat. I run the cheapest factory ammo that SGAmmo.com happens to have that week by the case, usually Sellier & bellot 115s or Fiocchi. Never an issue. When I first got my first one (the Gen2) I ran my -P pistol loads through it - subsonic 147s that barely made PF. They would run if the gun was very clean, but the cycling action felt sluggish and after ~150 rounds it would FTF intermittently till cleaned. Hot factory 115s feel exactly the same in terms of recoil, but run perfectly. I don't reload, so I can't help there, but a ton on this forum with MPXs do. If you get a chance at the range, compare an MPX running factory with anyone else running an AR9 where they've spent the time tuning the load and buffer to get it as soft as possible. The MPX will still likely win in terms of perceived recoil. Mine does to me. There are half a dozen guys I've shot with for years that are all running neat looking Lead Star game guns, and they all feel like jack hammers to me after the MPX.

Agreed with Startingover - ran a Taccom ULW for nearly a year in an MPX (USPSA/IDPA), and did pretty well with it, but double-tapping is harder. Switched back to a heavier 14.5" + comp and the second shots are automatic. Read the forums and you'll see the same comments come up: 1 - MPX shoots softer than a tuned AR9 with hot factory ammo 2 - This doesn't really matter for your split times Go with what you want. You can win with either. I find shooting friends AR9s jarring (I'm an MPX owner), but not any slower. If Lead Star would put soft-shooting gas piston actions in those beautiful skeletonized upper/lower frames I'd be all over it.

Not ditching the Timney. Tied for fewest points down at the match (down 6). Didn't miss the Hiperfire at all, though it does break with slightly less pressure. I did notice the wider handguard the few times I switched back to the Gen 2... the Gen3 PCC handguard is a very nice piece of kit. ~250 rounds or so over 12 stages - perfect function (I shoot factory 115s). The only time I had to work the charging handle was during the unloaded start stages. Very happy with it.

That's the PCC bug. Way lower after-beep stress levels, higher overall fun factor.

My Eclipse in the Gen2 does break with slightly less pressure, but it's not enough to ditch the Timney just yet. It's not affecting my times or accuracy. Shooting Silver Dollar with it tomorrow, so we'll see how it does under an all day match. I'll have both rifles in the cart, and may switch between them just to see if I can tell any difference after the timer goes off. It's an IDPA match - I shoot those for fun and the wacky stages.

Just got a new MPX PCC that will take over as primary - my Gen 2 will become the backup gun. While I love the Eclipse I have in the Gen 2, the Timney in the Gen 3 is really close... I'd strongly recommend shooting first before tossing one $250 trigger for another $250 trigger. It is a bit heavier, but it's not affecting my times or accuracy. The stock charging handle is still not all that great, though. This disappointed me. It seems to bind just as easy as the gen 2 did, and can still gouge the back of the upper despite the new tail on the spring retainer. The Next Level handle / spring retainer is massively smoother, plus has much wider latches. Handguard is amazing, and this is the first halfway decent folding stock I've seen. It has virtually no wobble at all. Sig is going to sell a lot of these.

A new MPX PCC plus optic and doo-dads (magwell, extended mag release) is about the same cost as 10 cases of ammo. ...ok, I'm not sure where I was going with that, but there must be some way to use that when 'discussing' the situation with the wife. I got lucky and was able to use proceeds from selling a few older rifles I recently inherited to buy a second MPX. Trying to fix it at the safety table isn't any fun at all, and many part failures (extractors, disconnectors, recoil springs, firing pins, tappets, etc.) require a full breakdown. Much easier to just grab the backup rifle and fix the primary after the match.

Gen 2 was fine, with a few early QC exceptions (feed ramp mis-alignment, etc.) You still will definitely want a Gen 3, though, until a new (or very lightly used) gen 2 drops down to a grand or less. You get a ton of stuff in the gen 3 that you'll pay extra for with a 2. Trigger, barrel with comp, better handguard, better stock, etc. I got an MPX pistol for $1100 new off Gunbroker early last year as that was the cheapest way to get into the gun, since I knew I'd replace virtually everything other than the upper and lower. After the hiperfire, ILWT barrel / guard, fixed tube & stock, it was still more than a new Gen 3 is now with all that stuff. You may still want a different tube/stock (I hate folders... they usually wobble a bit), but the rest is all good equipment. Here is a pretty in-depth review of the Gen 3 MPX PCC vs the earlier MPX Carbine by a competition shooter: http://thrumylens.org/featured/review-of-the-sig-mpx-pcc/

This was sound advice, especially since the trigger hasn't been completely out of the gun since I put it in last March. There were shavings, extra sear grease, etc., but the most likely culprit appears in the image. In my wife's words (she's holding the assembly) that spring 'looks pretty jacked up.' There's very little tension on the disconnector... I can see how it would grab when hand cycling using the charging handle, but not have enough tension when the bolt is at speed. There's a pristine spring in the original trigger assembly, but I've no idea how to replace that, and a quick googling doesn't show any instructions. I'll buy a new one and let let Hiperfire deal with it, and use it for a backup once it's working.

Oh, I'm not complaining (though I hope your fantastic ULW barrel lasts more than 10K... I've got 8K through it ), just trying to figure out the most likely fix before heading back to the range and maybe wasting a trip. Shooting a major next weekend and I really don't want to have to take the Tavor (love shooting it, but it's too slow), so I'll probably just order another ECL and send the first back to Hiperfire unless they just ship out parts. Triggers are wear parts, and from what I've read I'm lucky to get 10K. I'm very close to just buying an MPX gen 3 and use this gen 2 as backup and for steel challenge. We're spoiled here in DFW in that we can shoot 2 and occasionally 3 matches a week, every week, all year. Even without any live practice that really runs up the round count.

Less then 200 rounds through for the piston since cleaning. I've gone 10 times that. The bolt is coming back... the spent round is ejected, and a new round is fed in. The trigger just doesn't reset. When hand cycling the bolt with the charging handle the trigger resets long before the empty round would be ejected. I suspect disconnector failure of some sort, though I'm puzzled why it would reset with manual cycling but not when it's being cycled by the piston. Emailed Hiperfire, so I'll see what they say.

Have an ECL in an MPX with probably close to 10K rounds on it. Went single-shot at a match last week, and I assumed at the time it was the extractor spring (current one has ~5K rounds on it.) Turned out after testing it again at the range that the gun was extracting just fine... the trigger wasn't resetting. However, to make things more mysterious, it resets just fine by manually cycling it. This started happening mid-match, so nothing was changed or newly introduced. Is this more likely a simple spring issue, or something with the disconnector that Hiperfire will need to look at? I don't mind buying another ECL and sending the existing one back to be fixed (should have two anyway), but if a spring replacement is likely to fix it I'll try that first. I'd just do it and not bother the forum about it, but the closest range is 25 minutes away. Spending an hour in transit plus range fees for incremental testing isn't any fun, so if the consensus is a new trigger then I won't bother. It's also tempting to buy a new Gen 3 for a full backup... but that involves intensive wife negotiations. Daughter at college is siphoning off the excess cash.

Perhaps look into replacing the extractor itself? Shooting Sports Innovations and ILWT are carrying a billet machined extractor as an improved factory replacement. My factory spring went about 6000 rounds before it broke in half and stopped ejecting (in the middle of a match, of course.) A Taccom replacement just failed last week after about 3000. Another club shooter I've known for years has a 2017 Gen 1 that he's NEVER replaced any springs on, and it's got many tens of thousands of rounds though it.

0_o Is that an aftermarket thing? Or a factory variant? Those bolts aren't pulling tight.