quote:

Originally posted by Rangerone:
I received a response from the sales team of Geissele Automatics, and I was explicitly told that using their trigger in the MPX will void the warranty of the trigger.

So much for their golden warranty. I am very disappointed, though they have not tested it, and are aware of the forum talk about their triggers, they allow it to continue and it sells more of their triggers.

Legally, they have disclaimed by their note on their website, so let the buyer beware, use of their trigger voids warranty. Use at your own risk.

In my research, Geissele had said in the past that their "SSA" trigger is the ONLY trigger that will work properly with the MPX, and if the SSA fails they will replace at no charge.
So, is Geissele sales team now saying the "SSA" trigger and MPX are not recommended?

Yes, I sent an email late last week, and I got a response from them this week stating that using the SSA in the MPX will void the trigger warranty.

If you check the Geiselle website for the SSA, you will see their warning that their triggers are designed for the M16/AR15 rifles and not for MPX use. They go on to state that they are designing a SSA-MPX for release in 2017 and call for more details.

I think Geissele triggers are great, only that now there is a change in their support of their triggers in MPX. To be fair, they have stated that they have not personally tested their trigger in the MPX.

I wanted something in writing directly from Geissele and now I have it :-(

I don't think this will stop others from using the GA SSA trigger in MPX, and I am not advocating that anyone should not use it, only to communicate this current information, so others are doing so with the latest information.

quote:

Originally posted by Rangerone:
Yes, I sent an email late last week, and I got a response from them this week stating that using the SSA in the MPX will void the trigger warranty...

This is a disappointing turn of events.

Just got a MPX, to,use in USPSA PCC. Have been using a JP GMR-13. I like the magazine release, mag well, and hold open features of the MPX over the GMR. What I like most, is how soft the MPX shoots. Even with the OEM trigger, I can shoot the MPX faster than the GMR.

I started with the OEM 30 round MPX magazine, and it would not feed a round into the chamber, with the bolt not closing. Same with less rounds in the magazine. With the 20 round magazine, it wouldn't feed with more than 15 or so in the magazine.

Is this new magazine, stiff spring issues? All suggestions appreciated.

quote:

Originally posted by GJM AK:
I started with the OEM 30 round MPX magazine, and it would not feed a round into the chamber, with the bolt not closing. Same with less rounds in the magazine. With the 20 round magazine, it wouldn't feed with more than 15 or so in the magazine.

Is this new magazine, stiff spring issues? All suggestions appreciated.

What kind of ammunition are you using?

I've used FMJ (115 and 147), and GDHPs in my MPX.

The one round it refused to load consistently was our store reloads with Hornady 115 JPHs. Never figured out exactly why it hated those rounds--it loved the Gold Dots I fed it.

What kind of ammunition are you using?

I've used FMJ (115 and 147), and GDHPs in my MPX.

The one round it refused to load consistently was our store reloads with Hornady 115 JPHs. Never figured out exactly why it hated those rounds--it loved the Gold Dots I fed it.[/QUOTE]

I was using PMC 115 FMJ, which is the load I primarily use in the JP GMR-13.

I am only guessing, but it seems like the rounds are being pressed up so hard by the new springs, that it is preventing the bolt for going fully in battery.

I left magazines loaded over night, and hit the range today. Started with Lawman 147. First round appeared to chamber, but did not fire, and there was no mark on the primer. Through 25 rounds or so, there were a few more stoppages, then it settled down, and I went 100 rounds without a stoppage.

Some threads elsewhere mention an extractor and/or O ring being tight, until things break in.

Will shoot again soon, and hope it continues to run.

quote:

Originally posted by GJM AK:
Just got a MPX, to,use in USPSA PCC. Have been using a JP GMR-13. I like the magazine release, mag well, and hold open features of the MPX over the GMR. What I like most, is how soft the MPX shoots. Even with the OEM trigger, I can shoot the MPX faster than the GMR.

I started with the OEM 30 round MPX magazine, and it would not feed a round into the chamber, with the bolt not closing. Same with less rounds in the magazine. With the 20 round magazine, it wouldn't feed with more than 15 or so in the magazine.

Is this new magazine, stiff spring issues? All suggestions appreciated.

The magazine springs are tight. Leave them all loaded for 1-2weeks.
A previous post mentioned the spring putting so much tension on the rounds preventing the bolt from going fully into battery. This is correct.

My MPX still won't feed a round from a full, or nearly full magazine, inserted with the bolt forward. I need to remove 5 or 6 cartridges to get it feed. It does feed with the magazine inserted with the slide locked back.

I called Sig CS today, and they were quite helpful. They told me that the MPX was not designed to be able to strip a cartridge from a full magazine with bolt forward, that there just is insufficient bolt speed to make that work. I explained that was a problem with empty USPSA starts, and they suggested that I remove an O ring from the extractor, leave the magazines fully loaded to weaken the springs, and with time they should strip a round after the mag springs weaken.

Not the answer I was hoping for, but I appreciate their candor. 

quote:

Originally posted by GJM AK:
My MPX still won't feed a round from a full, or nearly full magazine, inserted with the bolt forward. I need to remove 5 or 6 cartridges to get it feed. It does feed with the magazine inserted with the slide locked back.

I called Sig CS today, and they were quite helpful. They told me that the MPX was not designed to be able to strip a cartridge from a full magazine with bolt forward, that there just is insufficient bolt speed to make that work. I explained that was a problem with empty USPSA starts, and they suggested that I remove an O ring from the extractor, leave the magazines fully loaded to weaken the springs, and with time they should strip a round after the mag springs weaken.

Not the answer I was hoping for, but I appreciate their candor. 

Mine took about 2 weeks loaded to capacity for them to all feed reliably.
Be patient, its not necessary to remove the o ring from the extractor.

Ditto. Same issue, same result after loading 30 and letting it stew for a few weeks. Or months
Runs perfectly now

Several weeks ago I took my new Gen II MPX Carbine out to the range, 0 FTF's, 0 FTE's, 0 issues, period.

This was a brand new gun right out of the Sig box, a little ALG Go-Juice, that's all.

500 rounds CCI Blazer Brass 124gr FMJ with one 5 minute cool down to change targets. I use an ALG ACT trigger, btw.

No issues whatsoever. Hmmm, it's only 500 rounds though.

Gen 2 MPX here as well (Feb 16) shortened to a 4.5" barrel, NFA Form 1 for SBR. I have the original 1 Gen 2 mag that came with it, and LOTS of Gen 1 mags and have yet to have a single feed problem with any. Several thousand rounds now, including Simulated FA with a Bumpfire (throwing LOTS of rounds out very quickly!), with a wide variety of ammo and no issues.

Which begs the question, why are some weapons so sensitive and others not? What's the element that's out of tolerance on some, but not on others?

Stock but cleaned up trigger by the way, about 4.5 lbs pull. It's not super crisp but I didn't want to drop a lot of cash on an Uber Trigger only to have it blow up. That latest generation of Franklin Binary isn't cheap but it speaks to me...

Enjoy!

Mpx mags hold 30 rounds of 9mm and with ten of them it takes a while to load not to mention what it does to your thumb

Got the RAE-711 loader that does 5 rounds at a time loaded three mags quickly and easily, you have to put it on top of the mag and hold almost flat. T\he rounds drop in unsecured and can flop forward or fall out if you hold it incorrectly.

I found stacking the rounds from the bottom up with it held back at a slight angle helps.

Then with a press of the handle the rounds enter the mag staggered quickly.

I also ordered the new Magula MPX loader and it should be here this week, it operates by a lever and inserts one round at a time, similar to other Magula loaders.

Then I can compare them, so far the RAE is simple but cumbersome.

I wish they made a Cammenga Easy Loader for the MPX. I use one for my MP5 and you can load 20 rds with one pull.

I noticed your loading Freedom Munitions. My Gen 2 won't run with Freedom Munitions 147 Gr, new rounds even when suppressed. Does like most other brand 147's though.

quote:

Originally posted by Ballistico:
I noticed your loading Freedom Munitions. My Gen 2 won't run with Freedom Munitions 147 Gr, new rounds even when suppressed. Does like most other brand 147's though.

I have issues with a few of my firearms with their re-man'd 147 grain but no issues with their new stuff. Have you tried any other firearms with their re-man'd stuff?

My gen2 (date on box is 11/18/16) does not like Freedom's 147 either. It will eat their American Steel 115 and Winchester Ranger 124+P just fine.
I have some WWB 147 somewhere and a few cases of Winchester USA 124gr FMJ enroute.

Going to look for some gen1 mags on sale.

Debating a barrel chop to 5" and rethread instead of buying a metric piston.

I have no issues with FM's 147 reman in my AR9 (4" sbr) suppressed or unsuppressed. It also runs fine in my Glock 19, Beretta 92F, Ruger 1911 and HK VP9 (suppressed and unsuppressed)

I've shot both new and reman through it without issues

quote:

Which begs the question, why are some weapons so sensitive and others not? What's the element that's out of tolerance on some, but not on others?

Drew816,
Good question and don't expect to get an answer from SIG CS. For FTF magazine issues, agree that mag spring tension is probably the issue and loading up the mag for about 2 weeks should work; also, load a mag with dummy ammo and cycle the action several times will help.

IMHO, in regard to suppressed or unsuppressed FTE issues, based on reading this forum and others, I think there is a manufacturing/assembly variability in the gas value block. Only solution for the MPX owner is to disassemble and thoroughly clean & inspect the value and Tappet per the tech manual. Make sure the value rotates freely in the gas block on reassembly. Depending on ammo, may have to clean & inspect more often.

Other than those suggestions, it is up to SIG to figure out and replace items that are "sensitive"; like SIG has done with the Gen 2 firing pin/bolt replacement.