It's a popular gun so I don't know why no one makes a suppressor specifically for it which coincidently would work on a lot of other guns nicely. I have two 9mm cans and neither works worth a damn on it. They both have boosters with right hand thread so when you thread them on it unthreads the booster. An AAC Evo 9 and a Silencerco Osprey 9. Someone should make a light weight, 1.6" OD can that has solid reverse direct threads and it would sell well. Standard 1.375" OD pistol cans are loud as hell.

Just to clarify, you are using a fixed barrel spacer to prevent the booster from moving, right? Otherwise you risk serious damage to the threads.

No offense, but I think your assertion that a very application-specific, larger than standard pistol-caliber suppressor for a carbine would sell well is a bit misguided. A lot of people stocked up before 41F passed or are waiting for the HPA to go through before buying silencers, which has impacted sales on existing designs, not to mention the R&D and production costs of a new design with limited utility.

Silencerco has this 9mm ASR muzzle device that was designed specifically with the MPX in mind.

https://www.store.silencerco.c...?variant=17796761476

This allows you to use the Hybrid suppressor with the ASR QD mount. This is the exact setup I'm using on my MPX and it works great. It does not loosen up when removing the suppressor.

They also just released a new 3-lug mount which works with the Octane, Omega-K, and Hybrid cans.

https://www.store.silencerco.c...?variant=35515080017

Got a feeling your not using a fix barrel spacer as stated above, is why your suppressor is unscrewing. And what ammo are you using ? I run pistol caliber suppressors on many different PCC using 147 gr and would say it's quite quiet !

Yes always use the fixed barrel spacers. I run 147 and 158 grain.

The suppressor unscrews because no one makes one with a booster that goes on with left hand threads so as you tighten the suppressor you have to stop twisting before you want to because if you don't the booster unscrews. Thanks Brett, I'll check that stuff out.

Considering how often SIG does the "Gen 1", "Gen 2" thing, I'm not surprised no one has invested the time and $$$$ to do this for an MPX.

Not sure what my overall ID is but my old Gemtech Tundra sounds just fine on my MPX with my 147 and 165 gr loads. It's louder with my shorter but fatter pos shadow ops 45 suppressor. I have not tried my old AAC Triad Ti .45 on the MPX.

Left hand thread is not always all it's cracked up to be. Especially in a can where the end caps are right hand thread. You can get to where tightening the suppressor down loosens the end cap and the end caps generally are not as easy to torque down.

I never knew the MPX threads went the wrong way.

I'd say Sig dropped the ball, not suppressors manufacturers.

And I'd also like to see a 1/2x36 direct thread option from manufacturers, but I'm not holding my breath.

I currently use a Osprey 45 with a fixed-barrel adapter and a 1/2x36 piston on my Palmetto PA-X9.

I had the same problem as Vapor Trail. The threads in the can for the piston or fixed barrel adaptor are right handed. The threads on the MPX barrel are left handed. You can't get both of them tight enough at the same time as one tightens while the other loosens. Rocksett on either of those threads was not an option as I didn't want the direct thread adaptor semi-permanently mounted to either the muzzle or can threads.

My solution was the ASR 9mm QD flash hider I posted above. I can tighten the flash hider down with a torque wrench, and use Rocksett to keep it tight even when it gets hot.

The ASR QD mount stays tight when you want it to, and loosens up when you want it to, thanks to the mechanical locking ring and teeth. Much better than a direct thread mount with opposing threads on the can and barrel.

A 3-lug muzzle device would work just as well for the same reasons. You can secure it to the barrel properly using Rocksett. You have to have a 3-lug adaptor for your can of course in order for it to work.

Doesn't B&T make a dedicated MPX can?

edit - yep. http://www.osagecountyguns.com/sd-988666-us.html

i guess I'm confused as why the 13.5x1 LH is the problem?

I just got a piston for my Osprey and it works great.

i guess the 4" barrel I have now is a 1/2x28, but it just needed a swap of the piston and it's good to go.

Stop being cheap and buy the proper mounts.

The Osprey with a fixed piston actually works pretty well, since it has the locking lever that prevents rotation of the piston. With that you can tighten it up to the LH threads of the MPX barrel pretty well. I used my Osprey 45 on my MPX before my Hybrid was approved.

But cylindrical cans, like the Hybrid I am using now, don't have that locking lever. So the only thing keeping the fixed barrel adapter in place are the RH threads of the can. So when you attempt to tighten it to the LH barrel thread enough to keep it from coming loose when it gets hot, you end up loosening the RH threads of the adapter in the can. Most cylindrical cans are this way. If Sig had used RH threads on the MPX barrel this wouldn't be a problem with fixed barrel adaptors.

quote:

Originally posted by RHINOWSO:
Considering how often SIG does the "Gen 1", "Gen 2" thing, I'm not surprised no one has invested the time and $$$$ to do this for an MPX.

^^^^^
This!

Three lug mounts are why. Those are the proper answer. I too first tried a LH adaptor on my MPX, and had the same problem. I couldn't get both the LH and the RH threads all tight. I chopped my barrel to 6", had it RH threaded, and attached a 3 lug. I am very happy.

Other than the tightening problem, the other issue with LH threads is that they are too thick. You can't put a 3-lug over them without making the adaptor overly long. Chopping and RH threading is the answer.

However, if I were Sig, I wouldn't offed a dedicated LH can, as customers can't use those on other most guns. I'd love to see Sig offer an integrated 3-lug directly on the barrel, a'la the B&T guns. Those guns are done right.

3 lug is the de facto standard for pistol caliber carbines.

I wondered why ILWT's MPX barrels were all .5x28, but BrettB's explanation cleared that up for me.

I've been super happy with my In-lead-we-trust 4" barrel. they sell barrels that have the 3-lug mount on them, too.

Wow, I didn't know about those barrels from In Lead We Trust. They probably weren't available back when I had my barrel chopped, but if I was getting another one, I'd be tempted to go with them. The real nice thing about the integral three lugs, is it keeps the overall package shorter. I bet compared to my 6" with thread on 3-lug adaptor, the integral probably knocks a full inch off the OAL with the can attached.