Waht to do with my Sig MPX rifle


Sep 1, 2010
New Hampshire
I apologize if this has been asked and answered but I have a Sig MPX rifle that I am considering converting into a suppressor host. Should I cut the barrel and have a 9mm suppressor pinnned and welded for a single tax stamp, has anyone done this.


Resident Phoenix Eye and Dim Mak Instructor
Jun 5, 2011
Pierce County, WA
Cutting and rethreading barrels is usually a waste of time and money.

Nobody here will tell you blind pinning or welding a damn can to a rifle is a good idea. If you're looking for validation on that I'd suggest trying barfcom or something.

And don't use a handguard that's longer than the barrel unless the can never comes off.

And even if does never come off, you still want the option for cleaning it. You also will require one with a positive latching system, not a direct thread or thread over --those will shoot loose. But QD cans aren't always easy to access under a handguard. Cleaning the muzzle is the hardest part on an integral weapon. And this wouldn't be integral mind you, it'd just a can stupidly welded onto the end of what was an otherwise fine rifle.

See why people don't do it? Other than Hollywood and people that think it looks cool but don't understand the weapon system? I suppose it has some narrow uses in the real world but I'm not aware of 'em.

Please send me your shit before you ruin it. I'm sure we can work something out.

On the other hand if you wanna save money and have a nice suppressed rifle, get a Sico Omega 9k and an ASR mount and call it a day. Won't add much length, will get the job done. I love this thing, my favorite 9mm can. If you insist on the short bbl., I don't blame you, just submit that on a form 1 and e-file it --it'll be back four times faster than your can's stamp will. Register the lower and you can get as many short uppers in as many variations as you like.

There's something to be said for SBR's and suppressed SBR's. I have rifles that are shorter suppressed than similar ones not suppressed. And long ones that only have maybe 4-5 inches added to achieve ear safe standards for intermittent noise. Like Saker for 5.56.

I blind pinned a pair of AAC mounts to a pair of LMT M4 rifles. I wish I could take it back.

Milo 2.5

The Dalai Lama of the Reload
Aug 7, 2014
Gillette, WY
Get the 2nd stamp, I differ from the others on cutting those metric threads off and doing 1/2-28. I have 2 Jp rifles, 1/2-36, 2 MPX's with their M33xpop me in the keister, it's a pain in the dick.


Feb 10, 2019
As others have suggesting, Form 1 it, and just purchase a 8” or shorter barrel (with a 3 lug). Then just buy a suppressor with a 3 lug adapter (I’d recommend CGS Mod9). If you want to go with something like a 4.5” barrel and an oversized hand guard you can, but don't plan on detaching your suppressor. You DO NOT want to have a hand guard go past your muzzle.
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