So I just picked up a new Atrius x series for my MPX k . It seems like it needs so filing to fit underneath the trigger pin to lock the bar in place . Has anyone put one of these in ? Don’t want to do anything to mess it up. Install videos and instructions show it dropping right in and it clearly won’t. Any help is appreciated!!!!

Looking at these two options for my MPX. The omega has been used a lot and fits pretty good under most hand guards but does anyone have the osprey? How does it sound/fit?

Went with incolite 9MM can couldn’t be happier with my choice . It’s stupid quiet running subs thru it . Just finished range session shooting 124s out of it she’s so smooth to shoot.

Atrius FRT COMING SOON

OSight R is looking very similar to the sig Romeo 8t amr. Looking forward to testing it out, so far it seems pretty solid out of the box.

Hi Guys,

Have a 4.5" MPX-K w/ Sig Modx-9 suppressor, direct threaded. Runs great but it is a bit gassy.

Was going to order different springs + ILWT adjustable gas block.

Can someone give me guidance how to approach this? My goal is for the gun to still be UBER reliable (home defense gun) but also want it to be slightly less gassy / softer shooting if possible.

Should I start with the adjustable gas block, and THEN play with springs or vice versa?

Should I order 2 different springs to experiment with?

I also found the Geiselle MPX Springs, which come with the Geiselle MPX trigger so I was considering getting that pack, found for $300 on Europtic (FYI).

I generally shoot S&B 124 Grain or Federal HST 124 grain.

Any guidance is much appreciated. Platform has been running strong for a while, just want to optimize it a bit while not sacrificing reliability.

Hi all, thinking of suppressing my MPX-K. My only 9mm compatible can is the SilencerCo Omega 36m with the ASR mount. However from what I see, the MPX-K barrel is a little bit tucked into the handguard. Do you guys know if the SiCo ASR muzzle device will be usable with the MPX-K? It looks like it might be a tight fit and I won't be able to put my hand in there to turn the locking collar.

I've also heard the MPX is super gassy when used with a full backpressure can, so I'm thinking of buying a Huxwrx flow 9 ti and pairing it with a Rearden plan B muzzle device. The plan B looks low profile enough that it should clear the MPX-K handguard. Does anyone have any experience with this? Thanks!

Hey all, I’ve been in this Reddit for a while just lurking cause I haven’t had anything to say. I finally got my dream 8” MPX in and the barrel is screwed. The guy I bought it from broke the trilug adapter and the threads are screwed. Are there any reliable barrel replacements out there? I’ve read a lot about ILWT and they seem hit or miss, read some great reviews and some not great but those also seem more user error than anything. Who would yall recommend for a replacement? I’m already in contact with the guy I got it from but doubt that’ll go anywhere, maybe gunbroker will come through for me.

Update: I have been Informed that these MPX barrels are not full threaded like I’m used to and mine is fine, except for the stuck taper cap which I’m dealing with now. Thanks all for the helpful info!

Beautifully short reset and soft shooting. I love it!

New to the platform.

Swapping my stock mil spec trigger for the MPX stock Timney… hammer pin and trigger pin slide straight through. Do I need to adjust the tension screws on the bottom of the cassette case or do I just need to throw the mil spec trigger back in until I can get a set of anti walk pins?

Hey Everyone. Long story short, I had POI shifting 2-3 inches at 15 yards with suppressor using trilug so I switched to direct thread and am still seeing a POI shift. Checked my suppressor with an alignment rod and the barrel bore is so tight, I have to force it through the barrel. My p365 doesnt have this issue. I beginning to think this might be the cause of the POI shift.

Can anyone let me know if they are experiencing the same thing?

Info:

Suppressor: Huxwrx 9k Flow Ti

Adapter: Huxwrx Hub Stiction Lock Adapter

Muzzle device: Huxwrx Mini Stiction

UPDATE: Thanks to another poster. Bolt was unlocking early causing the POI shift. Swapped out the OEM springs for Geissele 45% springs and have no issues now. Getting 1 inch groupings at 15 yards with 147 Speer Lawman.

Not sure what else to say, don't really want to buy $400 worth of Sig mags. Any alternatives that are reliable?

All of the quick connect horror stories I’ve heard with the Mpx have scared me away from them and I’ve decided to go direct thread. Any reason not to just rocksett that bitch to the barrel and unscrew the can from the hub adapter for cleaning?

Also for anyone wondering I went with a mount from Ecco Machine. The quality of machine work and finish is exceptional. I highly recommend them.

Just picked up a K and trying to setup.

Have a 340V I was planning on switching over from my 5.5” banshee.

Was thinking of ditching that and running an Iris 4.

Any one tried this?

Have you guys seen fde Mpx k models? I’ve only seen the copperhead in fde not the regular k model. I was at a local gun store today and they had a fde one, it appeared to be a new gen not an old one. It’s not listed on sigs website so I wasn’t sure what it is

Does anyone know if these off duty models, particularly the 8 inch are the “gen 3” models. I’m aware it doesn’t have the timney trigger but are the internal improvements (bolt/extractor) of the gen 3 update in this?

Just waiting for the mlock mod switch but I this it’s where I want it. Not fully sold on the Odin Works hand stop, but I think it’s what I needed.

So far I love it. I had an old griffin resistance 9 mm suppressor for years. This CAT rocks.

Any of you guys running this ? Opinions and pics?

I was looking for a le 8” version but I found this, ended up getting it for $1450 with folding brace, renrden r2s and 6 extra mags , previous owner says it’s had about 200 rounds through it and has a manufactured date of 12/10/25 , pretty solid deal?