quote:

Originally posted by Shackelford:
LDD, awesome write up.

One question, though...

The "monolithic" rail that's one-piece to the upper only sticks out from the upper about 3".

The arrow in the below photo points to the end of the receiver rail. The last 1" of rail is from the handguard.



Let's say you want a "briefcase gun" 4.5" bbl with the short handguard. You add the 4.5" bbl and the short handguard adds about 1" to the existing upper rail.

So you're done with your business meeting, and now you want to go to the range and would like a longer barrel and handguard. You pop the 4.5" bbl off, and add a 8" bbl. You also add a 8" thread-on suppressor. Well, can't have a long bbl and a short handguard, so you take off the shorty handguard and add the long 12" handguard (handguard is 12" long, but the rail on top is only about 9" because you already have 3" of rail from the receiver) so that about 4" of your suppressor is covered up.

So you've basically gone from a "K" configuration to an "SD" configuration using the same receiver and four different parts.

If you look in the 7th picture, behind the bbl is the rail. That's how much rail you are obligated to have. Any additional rail is as a result of adding a longer handguard.

quote:

Originally posted by bigpond73:
A great write up, thank you! One question though, the magwell seems huge, and the mags, well, proportional. Is there a reason for that? Maybe it's just the lighting?

The magwell is flared I've seen more obtrusive flaring on some HK pistols ("Jet Funnel").

The magazines aren't that big or blocky but they are polymer.

Compare a G17 magazine to a P226 magazine. Then take that analogy and apply it to an MP5 magazine.

Polymer is going to have to be thicker than sheet metal to maintain the same strength, particularly a clear polymer.

They are fatter than an MP5 magazine, but not obnoxiously chunky like UMP magazines.

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

I'm still a bit sad that they didn't make a domestic version of the Famae SAF. Alas, it looks like a nice bit of kit. I'm kind of surprised that the QD sling sockets on aluminum lowers aren't just screw together steel parts on both sides of the receiver. I'm no designer or engineer, but it seems like an easy fix to me.

Thanks for the very detailed write up.

quote:

The MPX will first be released as a 9mm . . .

. . . 12” + ~4” moderator (for 16+ non NFA OAL bbl length).

This is what I was hoping for, and to me makes more sense than a 6.5" barrel, with a permanently attached 9.5" device that is currently shown on the website. It appears I will need to start saving up for one.

quote:

Originally posted by DMF:
Thanks for the very detailed write up.

quote:

The MPX will first be released as a 9mm . . .

. . . 12” + ~4” moderator (for 16+ non NFA OAL bbl length).

This is what I was hoping for, and to me makes more sense than a 6.5" barrel, with a permanently attached 9.5" device that is currently shown on the website. It appears I will need to start saving up for one.

The intent behind the MPXc is actually quite novel.

The gun would start out as an 8" bbl with an 8" brake.

It would be title 1 (non-NFA) in that configuration.

But, for an additional $200 (+$200 NFA stamp), SIG would sell you a sleeve that screwed on to the end of the brake, turning the brake into a suppressor. The sleeve would be the serialized part.

Being able to sell one model to both NFA legal and NFA restricted states has a lot of efficiency benefits.

quote:

Originally posted by LDD:

quote:

Originally posted by DMF:
Thanks for the very detailed write up.

quote:

The MPX will first be released as a 9mm . . .

. . . 12” + ~4” moderator (for 16+ non NFA OAL bbl length).

This is what I was hoping for, and to me makes more sense than a 6.5" barrel, with a permanently attached 9.5" device that is currently shown on the website. It appears I will need to start saving up for one.

The intent behind the MPXc is actually quite novel.

The gun would start out as an 8" bbl with an 8" brake.

It would be title 1 (non-NFA) in that configuration.

But, for an additional $200 (+$200 NFA stamp), SIG would sell you a sleeve that screwed on to the end of the brake, turning the brake into a suppressor. The sleeve would be the serialized part.

Being able to sell one model to both NFA legal and NFA restricted states has a lot of efficiency benefits.

I agree it's a great idea for those that want the option to easily/efficiently add a silencer option. However, for those of us not interested in getting involved with NFA firearms (or those unfortunate enough to live where the they don't have the choice), the 12" barrel idea seems to make more sense.

Sig definitely benefits from the efficiency of the 8" + 8" idea, but for the customer it's only a benefit if the customer is considering going down the NFA road.

Regardless, if it proves to be reliable in the 12+4" configuration, I could be spending the money to get one, as I've wanted a 9mm carbine for a while. I've been putting off searching for a Beretta Storm in hopes of getting something better, and this looks like it may fit the bill.

Thanks LDD. Great info!!!

quote:

Yes!

But unfortunately...
this fine piece will not (legally) be available for about 99% of civilian/private gun owners over here.

So I will have to remain with my "brick-in-the-box" HK USC (as long as we still have them legally over here...).

Anyway, what a fantastic report! Thanks a lot.

Thank you; great report on a fine weapon. I only wish Sig came out with it in a more potent round, either a .45 or developed a round that was more powerful than a standard sidearm round, as even the U.S.Army has conceeded that the 9mm is not hard hitting enough for a sidearm. Has there been any thought of a harder hitting round for this in the future like the .45acp, or even something like a .30 carbine round? Thank you again for the fine work

Utah, get me two!

Excellent write up. Thank you for sharing that with us.

LDD a question for those of us who will go down the NFA road.
How easy is it to add the stock to the pistol versions or to the SB15 version ?

quote:

Originally posted by LDD:

quote:

Originally posted by bigpond73:
A great write up, thank you! One question though, the magwell seems huge, and the mags, well, proportional. Is there a reason for that? Maybe it's just the lighting?

The magwell is flared but not I've seen more obtrusive flaring on some HK pistols ("Jet Funnel").

The magazines aren't that big or blocky but they are polymer.

Compare a G17 magazine to a P226 magazine. Then take that analogy and apply it to an MP5 magazine.

Polymer is going to have to be thicker than sheet metal to maintain the same strength, particularly a clear polymer.

They are fatter than an MP5 magazine, but not obnoxiously chunky like UMP magazines.

Thanks for explaining that LDD. I can see it now.

quote:

Originally posted by KML:
LDD a question for those of us who will go down the NFA road.
How easy is it to add the stock to the pistol versions or to the SB15 version ?

Stocks attach via pictinny rail at the end of the receiver.

If you can insstall a riser, or backup iron sight, flashlight mount, etc, you'll be able to install a stock/pistol brace on the MPX.

I love my AR SBR 9MM, but if the MPX delivers I'll be buying one.

Probably a pistol with SB, then SBR it. Time to save my pennies!

As always, excellent report. Thanks for point out the mono rail. I was a little confused during the first read and going from pistol to rifle.

Did you see any examples of the 12" brl with 4" FH?

Great write up LDD.

I have a question regarding the handguard. How does the handguard attatch to the weapon and is it secure with no play when attatched?

Wow, great write up.

The MPX and conversion kits look like they'll money vampires for me. I'll take one of everything, especially .357 Sig.

quote:

Originally by Blackwater: Did you see any examples of the 12" brl with 4" FH?

Did not see any examples of this model.

quote:

Originally by tpd312: I have a question regarding the handguard. How does the handguard attatch to the weapon and is it secure with no play when attatched?

All of the examples I saw were quite secure, but I never got a chance to take the handguard off so I can't accurately describe how it attaches. We only saw the guns with hand handguards off once and I was standing at a bad angle to see the locking mechanism.

LDD I'm sorry if I missed it but any idea on MSRP?

quote:

Originally posted by KML:
LDD I'm sorry if I missed it but any idea on MSRP?

I see MSRP of $1999 listed for SGMPX-9-P (6.5" pistol variant) and $2199 for a 16" rifle model, but it's hard to tell what exactly you are getting from the older photos.

So I see them selling for $1600-1800 probably.