Purchased my present GEN 2 MPX (have several 20 + 30 rnd GEN 2 mags) Nov.2016 Did some plinking w/ it thru the winter, then finally used it at several USPSA matches here in Maine. Seems i could not finish the match at the last 2 stages. Seems gun would double feed or FTE about 125 rounds into match. Using 124gr Federal or ZQI bullets. Finally called SIG and talked to Mike, he had me ship it to them.Upon return service receipt read:Inspected rifle,replaced gas valve,extractor spring and insert. Tested w/Gold Dot 124gr,no malfunctions thru 50 rnds.Got it back w/ a quick clean, Thought i would load up all my mags 3-30s and 3-20s and run them thru rifle and it still stopped working at about 125 rounds Cleaned it, took it to a recent match and it gave me FTF and FTE again. So between stages i tore it down for a quick piston valve cleaning to get me thru. Side bar:should i be using Lucas oil or Lucas grease on Tappet and in gas block or run it "dry". Any help is appreciated, thanks in advance

So far w/ post at 90+ views w/ no replies, guessing viewers are not shooting an MPX have i posted this issue in the wrong category Where are all my fellow MPX shooters "hanging out"

Maybe you need to post it in Mason's Rifle Room category.

OK thanks, I'll give it a try

I have had no issues of any kind in either of mine BUT I have only run factory ammo. Not clear if you have the issue with factory ammo, otherwise you know the drill its the ammo. In any case the gas system should not be lubed.

At one USPSA match and one (125rnd) test run i was using Federal 124gr and ZQI 124gr bullets when i got FTF and FTE's

I've no issue using 124g stuff but have you tried to run something a bit zippier like Winchester nato? I do a bit more ammo sampling to see especially if what you've been running has all been from the same batch/lot/mfg.

I bought a bunch of leftover MPX mags off another internet friend who sold his because of feed issues that Sig couldn't fix on his gun. Ill ask him what issues he was having exactly and what repairs sig tried

Good stuff, thanks for the replies and keep em coming.

I talked to my buddy. He said

"I didn’t have double feed issues, straight up got stuck on the ramp, wouldn’t feed. Had to run no more than 25 in a mag, my MPX had to be spotless and over lubed. It started feeding after around 3 mags worth of miss feeds.
Sig changed a firing pin that broke (yeah that also happened) and sent it back with “found no other issues”."

I have a gen 2 I bought from someone else. When I got it, the round count was about 500-600 as per the prior owner.

I have 5 gen 2 mags and 9 gen 1 mags, all 30 rounders.

With that said, I have never had a FTE, but I get FTF at least once per mag, and it doesn't matter which mag.
When it jams, I find the fresh round stuck nose up into the top of the locking lugs, or with just the tip into the chamber and the rim hung up on the bottom.

All my 9mm is speer gold dot 124gr +p factory. (I get it from work)...

When it runs, it will fire as fast as I can pull the trigger, but it may fire 20 rounds and then I get a *click*. I look and the bolt is halfway forward with the round pointing up at a 45* angle. So I drop the mag, and pull the bolt back and most times the round drops free. Sometimes its jammed in hard enough I need to flick it out with my finger and when I look at the round it had a dent in each side of the hollow point where it was jammed into the top of the chamber.

I have cleaned and scrubbed it down with all parts broken down, relubed all parts to Sigs recommended levels, and have also tried it to what I would call "over lubed and very wet". Nothing has fixed it yet.

I may call sig in the near future and send it back. It seems these are hit or miss. Some people will claim they have 5K rounds down the pipe without a single jam, others are like me where you cant get a full mag off without having to clear a FTF or a FTE. It seems there are lots of people complaining and sig is quick to send you a prepaid label to send it back for service. Makes me think there is some design flaw and we will probably see a gen 3 or a retrofit kit offered to fix these problems.

Thanks for the reply NYresq

I have 2 MPXs
They both have only 5-800 rounds through.
I've had that problem with my mags that have Taren Tacticle plus 10 extensions on, with their springs.
I've come to the conclusion that there is too much upward pressure on the bottom of the bolt, when the mags are fully loaded. Currently, I have had them fully loaded for the last two weeks, in an attempt to relax the springs.
I don't have any issues with the factory mags.

Thanks for the reply RH45. I also have a 30 round Gen 2 mag w/ a Taran Tactical extension,but do not recall at the start at a Match shooting stage when i was loaded up w/ that particular mag on problems w/ FTF or FTE. Since the last match during the summer of 2017. I have not been leaving any considerable amount of grease or oil on the Gas Valve, Tappet or in the gas block.(keep it dry,so i am told) Plus i keep the carriage assembly and it's components well lubed now.Been shooting 124 & 147 grain bullets,so far so good. Sidebar: I see Taylor Freelance has MPX mag extensions which still use the original mag springs and are less $ than Taran Tactical.

I'm not sure this is helpful. But I have been shooting my MPX in our weekly indoor matches and loaning it to someone else to use as well. So since October its now been 5000 rounds since I last cleaned it. I did squirt a bit of CLP in there recently as it looks pretty dirty.
Using stock Gen2 mags and Winclean (not known to be zippy but I need to manage my lead indoors) there have been zero failures. That's on top of another 5K rounds I did on another MPX over the summer no issues. Of course sometimes individual guns matter so if you are still having issues I'd send it to sig.
If you are using modified mags, non factory/reloaded ammo and other non standard stuff, the issue may be on you.
I did just get a bunch of the Taylor extensions I'll let you know how the run after next Thursday's match.
FWIW>

I've been having all kinds of issues getting my MPX to feed various types of ammo. When mine jams, the round is stuck sticking up at about a 45 degree angle between the bolt and the barrel. I found a thread over on AR15.com that has made a night and day difference for me. I've been struggling with this for quite some time and had almost given up. I don't know if this is your issue, but check it out. Maybe it will help.

https://www.ar15.com/forums/Ar...TH-BOTTOM/45-486639/

You guys just saved me a bunch of money was thinking about one of these but not with those kind of issues. Mag issues are the worst the doubt always lingers about them

Update: i have shot 2 USPSA matches so far this year w/ MPX and Gen2 mags and it ran great, no FTF or FTE.Using my reloads of 124gr. or 147gr. Fellow shooter goes to SIG Academy at least once a month. Said they keep there MPX's well lubed (probably LUCAS gun oil) and keep the piston clean n dry (not lubed)I for some reason early on felt the gas piston had to be lubed.Was not a good idea by me