Cutting MPX / MCX barrels

[JCN]

Hi guys, I’m still new to long guns.

Is there a place people trust / like to cut a 16” barrel down to an 8-11” size?

With the MPX the gas block is near the chamber so probably fine, but with an MCX looks like it’s farther out towards the muzzle?

Would cutting an MCX be a bad idea because of lack of dwell time? It seems like that to me perhaps.

[Default.mp3]

AFAIK, the MCX barrels (outside of the Rattler options) have the gas blocks in the same place for each caliber. Dwell time will definitely be an issue, but it's also manageable, given the design parameters, so nothing something I would worry about here. The difficulty of the actually chopping an MCX/MPX barrel is probably the tapered shoulder, which may be a moot point if you don't care about that. Beyond that, there is the question of needing to open up the ports in the gas block for proper functionality; if you stick with a factory length, would probably be easy enough to just ape what SIG used for their port sizes, but if not, there might be some SWAGing involved.

[JCN]

I saw on SigTalk that someone had good success cutting a 16 down to 11.5.

For me it would be to run suppressed so I would probably get back some reliability in the gas system that way.

[Default.mp3]

For me it would be to run suppressed so I would probably get back some reliability in the gas system that way.Don't the MCX use an AGB? So cutting it down without adjusting the ports would probably work okay if you're running it dedicated suppressed, since you can just use the 16" unsuppressed setting, but then the 16" suppressed setting is now useless, and you're SOL if you're ever going to run the rifle unsuppressed (which to me is one of the main advantages of the MCX, the ability to natively fold into a small package) or use a low backpressure can.

[CleverNickname]

I literally just sent out a 16" 5.56mm MCX barrel yesterday evening to get it chopped to 14.5". From what I read from other people posting online, they didn't need their MCX gas ports adjusted when cutting from 16" to 14.5", so I'm hoping that's accurate. I guess I can always have the gas port opened up more later if needed.

[Casual Friday]

I think I'd sell the 16" barrel and just buy the 11.5", unless the cost of chopping, threading, and potentially opening up the gas port is less money than the offset cost of selling one and buying the other.

[JCN]

I think I'd sell the 16" barrel and just buy the 11.5", unless the cost of chopping, threading, and potentially opening up the gas port is less money than the offset cost of selling one and buying the other.

Are there 11.5”s available? They seem unobtainium. I would gladly buy one if I could find one under $1k.

[Casual Friday]

Are there 11.5”s available? They seem unobtainium. I would gladly buy one if I could find one under $1k.

I don't know, I was just trying to offer the easy button solution. Wait times for reputable shops are often measured in months or more.

[JCN]

I don't know, I was just trying to offer the easy button solution. Wait times for reputable shops are often measured in months or more.

That’s like saying “let them eat cake…”

The 11.5” is really hard to get and backorders from Sig have been 18 month + on them.

So I’m this case, the easy button is actually to get a Smith to cut a 16” and SBR it while waiting for the Smith…

[Casual Friday]

That’s like saying “let them eat cake…”

The 11.5” is really hard to get and backorders from Sig have been 18 month + on them.

So I’m this case, the easy button is actually to get a Smith to cut a 16” and SBR it while waiting for the Smith…

Then I'd contact D Wilson Mfg and see what they can do for you. They do excellent work but can get backlogged, but I think they got a new facility and increased production since I had them convert a standard barrel to fit my LMT MRP upper.

[S Jenks]

I’ve had good luck with Adco in the past. I’ve had them cut and thread an AWB-compliant S&W AR barrel from 16” to 11.5” and cut threads for an Uzi Pro barrel. Both came back looking like they had been done at the factory.

https://adcofirearms.com

[Tokarev]

Parker Mountain Machine has probably done as much with MCXs as anyone. I'd drop him a line with questions about barrel work.

Sent from my SM-G970U using Tapatalk

[JCN]

I’ve had good luck with Adco in the past. I’ve had them cut and thread an AWB-compliant S&W AR barrel from 16” to 11.5” and cut threads for an Uzi Pro barrel. Both came back looking like they had been done at the factory.

https://adcofirearms.com

Great! Jenks comes through again!

They even have a special link for it.

https://adcofirearms.com/shop/gunsmithing/threading-fn-scarcz-brensig-mpx-barrels/