Mornin', fellas!

I helped infect a friend with the SIG MPX bug...he now has more of them than I do, and is planning to make one a suppressor host. I figured why google in the dark when I've seen plenty of people showing off their rigs here.

So...who's made their MPX quieter? And how?

-Did you go with the 8" upper? 4.5" upper? SIG's "suppressor ready" build with the 4.5" barrel and faux can under the 8" hand guard? Or something totally else?

-Which cans have been effective for you?
-How is the gas blowback?
-Can you mitigate overgassing with a charging handle?
-I've heard about In Lead We Trust barrels. Good/Bad/Ugly?
-What fits/doesn't fit under the handguard?
-How did you solve mounting solution challenges?

Asking for a friend...but when I stop moving every damn year there will be NFA in my future, so...thanks from the both of us!

PS: Just because he frequently sends me goodies to drool over...don't forget the pics!

I have a gen1 MPX - bought one of the earliest models (back when they came with a hard plastic case).
It came with an 8" barrel - I had it chopped down to 5" and put a SiCo Omega9k on it.
Works like champ and fits nice and happy under the handguard - pokes out about an inch or so.

I don’t have any pics yet, but waiting on a Rugged Obsidian 45 can stamp, was submitted right when the government shutdown was starting, so I probably still have a few months to wait. Bought the can to go on an MPX-PSB with the 8 inch barrel. The Obsidian is convertible to a short configuration which is how I am planning to run it. I have a 13” hand guard, so it should cover all but the last inch or two of the can. I have it topped with a Sig Romeo3 reflex sight on the riser. Oh, and it has a Franklin binary trigger.

I bought the 4” In Lead We Trust barrel when it was first offered, and it came 1/2x28. I then got the Lancer carbon fiber 4” hand guard. I only have a SiCo Osprey 45. It wont fit under the handguard so i use a small spacer washer threaded onto the barrel and the extended SiCo 1/2x28L piston to allow it to thread on tightly. It works well. Its pretty quiet. Not much by way of gas to the face ive noticed. My wife enjoys the MPX so much shes claimed it as her own - first gun ive owned that she’s liked that much so I welcomed it.

Here's my wife's MPX with my two Daniel Defense rifles for a suppressed family photo as the most recent photo of the MPX:


Here's the photo of my buddy's MPX back when he had an FFL/SOT shop - full auto sear, Omega 9k (I think?), SBR'd MPX:

quote:

Originally posted by PorterN:
I bought the 4” In Lead We Trust barrel when it was first offered, and it came 1/2x28. I then got the Lancer carbon fiber 4” hand guard. I only have a SiCo Osprey 45. It wont fit under the handguard so i use a small spacer washer threaded onto the barrel and the extended SiCo 1/2x28L piston to allow it to thread on tightly. It works well. Its pretty quiet. Not much by way of gas to the face ive noticed. My wife enjoys the MPX so much shes claimed it as her own - first gun ive owned that she’s liked that much so I welcomed it.

Here's my wife's MPX with my two Daniel Defense rifles for a suppressed family photo as the most recent photo of the MPX:


Here's the photo of my buddy's MPX back when he had an FFL/SOT shop - full auto sear, Omega 9k (I think?), SBR'd MPX:

I recognize that wall (I'm pretty sure)! Didn't realize MTR closed, bought my first suppressors from there when I moved to Utah.

Youre right! I need to text Brandon and ask him wtf, yeah.

Yeah I'd be curious to know what happened. His shop was awesome (very nice differentiator to have everything mounted up to a gun as opposed to the usual glass case full of metal tubes that all look alike) and he wasa good guy to chat with and was very enthusiastic about what he did. I wonder if the the significant increase in Silencershop dealers in the area over the last couple of years pulled business in other directions, especially for people like me in Salt Lake county that didn't really have many closer options until recently.

I have a Gen1 MPX that started off 8". It was threaded from the factory LH. At first I tried a direct thread can, but the mount to can interface was RH threads, and mount to barrel was LH, it was impossible to fully tighten. I sent it off to be cut to 6" and threaded 1/2x28 RH. I then installed a 3 lug mount. Three lugs are the way to go. My recommendation is to keep your barrel factory, and get an ILWT with integrated 3 Lug.

I use both a Gemtech Multimount and a Griffen Revo9, the latter usually in the short K config. Both fit under the handguards nicely. The gun still felt a bit heavy for a PCC, so I swapped out a 8" Lancer carbon fiber handguard. That really helped with balance, she feels like a dream, now.

A Radian Raptor MPX charging handle helps with gas, but there is still some gas in the face. It mostly depends on ammo though, some is much worse than others. I've been considering a new gas plug from ILWT, to try and cut it down further.

Last upgrade was a Larue trigger. Larue claims that it will hold up to an MPX, we will see, but that thing is every bit as good as a Geissele.

I have also found the 3 lug is the best way to go, for me. No problems with carbon lock. Fast, reliable connection. No threads.

My 8” MPX is awesome with my Griffin R9 using the three lug attachment. But my 4” K has been more problematic. Great with the piston and fixed bbl spacer. Not great with the three lug - significant and erratic poi shift. I don’t like the piston setup so searching for something better, I found that the Silencerco Alpha fixed bbl mounts for the Octane will interchange with the Griffin and they offer a M13.5 LH which Griffin does not. So I’m going to try that next.

BTW also using ILWT taper collar on both to square things up better than the muzzle face can.

I’m debating on suppressing my MPX carbine, the original release with keymod hand guard and the 13”(?) barrel with the long pinned FH. Thought about either getting a 16” ILWT threaded barrel that I can put a 3 lug on, or SBRing it and going with a 6-8” 3 lug barrel. The SBR route is going to be more expensive with the price of the stamp, engraving, and a new shorter handguard. Heard mixed reports on how gassy the MCX is.

I also had problems keeping the mount tight with the mixture of RH and LH threads using a fixed barrel adapter on my factory 8" MPX barrel (Pistol that I SBR'd). The Osprey worked great as a direct thread though since it has the locking lever that allows you to crank down on the LH barrel threads.

Currently using the Silencerco ASR 9mm flash hider and a Silencerco Hybrid with 9mm endcap. The ASR mount works great. It's QD, locks up rock solid, no POI shift. Shooting subsonic ammo it's incredibly quiet, much quieter than any of my friends 300BO rifles with subsonics. Very smooth shooting and ridiculously fun. Several thousands of rounds through this little SBR and not a single hiccup.

I've used 3 different cans (Hybrid, Osprey, and Obsidian 9), with a half dozen different kinds of ammo, and I have never experienced any gas issues at all on my MPX. I own and have shot several suppressed semi-auto rifles that DO have gas issues and my MPX is not one of them.

I have the 8” pistol. I forgot who I had cut the barrel to 4” and thread in 1/2x28.

I’m using an old Gemtech Tundra. I’m looking into one of the recent short suppressors. Specifically the Dead Air Wolfman.

I’ll post a pic later. I just removed the original brace recently so it’s on the workbench.

It's got the Tundra in it. This is why I want a shorter suppressor.

This message has been edited. Last edited by: Phelen_Kell,

Mine sounds great with the SilencerCo Octane 45HD and 9mm end cap, 3-lug attachment. With 124gr, 147gr, 158gr and 165gr HUSH it has been my experience that I notice next to nothing coming back at me. That's with both the 45 end cap and 9mm end cap. Started with the factory 8” barrel, had it cut down to 4” by ADCO.

Mine isn’t too gassy. It depends on brand of ammo. One or two can be foul, but most ammo I shoot gives me no problem. If it does bug you, you can try an ILWT gas plug to tone it down.

I have a second gen MPX that came with the 8" barrel. I changed it to a ILWT 4.5" barrel with the integrated 3 lug and have a Griffin R9 on it. Did the Form 1 to make it a SBR and put an adjustable stock on it. Works flawlessly so far. No noticeable blowback, but it is a bit dirtier when I take it apart.