What a fantastic review! But, uh oh, the next wallet draining platform has arrived.

I have not been interested in anything from SIG for a long time, but this certainly looks good.

quote:

Originally posted by beefangusbeef:
I have not been interested in anything from SIG for a long time, but this certainly looks good.

I can say the same thing.

I was an early adopter of the Sig 556 and got burned. I've not looked at anything Sig has offered in quite some time but this has a different feel to it.

I'll wait, this time, for the early reports to come through but I'm not sure I can resist a quality pistol carbine like this looks to be.

Nice write-up LDD. I think I will SBR it then turn it into a pistol

Updates from SIG from my last round of questions:

1) The MPX will ship with one magazine (like all SIG rifles).

2) .357 SIG/.40 versions of the MPX do exist now, but there is no ETA for their commercial release.

3) Kits/bbls/conversion parts will be available for purchase as their corresponding models become available (e.g. the .40 conversion will become available when the complete .40 guns hit the market). Same with the different lengths of bbls in 9mm.

When they release, MSRPs for the .40 and .357 SIG models will be the same as 9mm.

4) MPX SBRs will initially ship with three-position sliding stock. Folders, including the Kate Moss will be available for purchase.

quote:

Originally posted by LDD:
3) Kits/bbls/conversion parts will be available for purchase as their corresponding models become available (e.g. the .40 conversion will become available when the complete .40 guns hit the market).

Ahem... That reminds me of the promise H&K gave us USC buyers when the USC hit the market. Instead, to the present day there are no USC barrels/conversions (to swap calibers) available here.

Perhaps SIG does better...

A pistol version with a folding brace sounds fantastic, in any caliber.

If only they/someone would make a 10mm conversion I'd be delighted beyond words. Real MP5/10s are way too expensive to be practical users for mere mortals. Maybe a .40.version could be modded. (one can dream...)

Are any of our vendors able to order these?

Great write-up. I had seen a couple of days ago that the MPX had hit the "available" list that our new rep had provided us (16" carbine and pistol) when I was looking up the P226 Combat (not currently available, btw) for a customer. We had a handful placed on order from 2013 SHOT; dunno if our buyer kept those active given the ungodly (from a business perspective, mind you) amount of unsold black rifle--and consequently the tied up cash--we've still got loitering in our back stock.

BTW, if anyone from SIG happens to be reading this thread...I for one miss our OLD rep, you know, the fellow who drew his paycheck directly from YOU. These outsourced guys so far are NOT the most responsive of folks (maybe they're still learning the new SIG part of their business...or maybe not, given how poor our previous support had been for a certain domestic optic manufacturer, which was a product line they used to rep but dropped to pick up this juicy SIG line), but the fellow who handles OUR account so far has been less than impressive. If this is an example of one of Cohen's ways of improving things for us in the peanut gallery, so far it ain't workin' so well.

Sig just put up a link on Facebook to here talking about the MCX. Good job LDD!

quote:

Originally posted by IrishWind:
Sig just put up a link on Facebook to here talking about the MCX. Good job LDD!

Thanks for the heads up IrishWind.

New MSRPs from SIG:

- MPX-9-P, Pistol, 8” bbl, aluminum handguard - $1,599.00

- MPX-9-P-PSB, Pistol, 8” bbl, aluminum handguard, SBX on folding knuckle, $1,732.00

- MPX-9-SBR, SBR, 8” bbl, aluminum handguard, telescoping stock, $1,799.00

***

I think it's safe to say the 8" bbl'd models will be among the first out.

While MSRP usually hits above street pricing, I would expect the first run of MPXs to sell at or above MSRP due to demand.

Again, a big thanks to the folks at SIG for access to the MPX.

LDD


I just fired my lightweight barreled AR and forgot how hot that thing gets after a few mag dumps.

How hot did the standard handguard get? Was there a difference with the Keymod?

Those MSRPs aren't as bad as they once were. I'm interested to see what the MSRP on the carbine version will be.

quote:

Originally posted by Fourxfour:
How hot did the standard handguard get?

We were firing on full auto, mag dumps as fast as we could change shooters.

It got hot enough that it'd scald you within the first second of touching it. The MPX was not designed as a weapon from which to deploy a sustained base of fire, so we were probably using it outside its design specs. However, with a VFG we were fine. The handguard got hot but the weapon did not fail, which is the important part.

quote:

Originally posted by Fourxfour:
Was there a difference with the Keymod?

The KeyMod handguard was also aluminum, and the one we were shooting on was the K model, so it was even shorter than the 8" (so it had even less surface area with which to radiate heat from). The material is probably the same composition of aluminum so I would guess that the rate of heat radiation is the same, all other things being equal (given equal sized handguards). Actually the KeyMod probably has less surface area since the KeyMod holes are bigger, thus resulting in less overall surface area from which to radiate heat.

quote:

Originally posted by LDD:

quote:

Originally posted by Fourxfour:
How hot did the standard handguard get?

We were firing on full auto, mag dumps as fast as we could change shooters.

It got hot enough that it'd scald you within the first second of touching it. The MPX was not designed as a weapon from which to deploy a sustained base of fire, so we were probably using it outside its design specs. However, with a VFG we were fine. The handguard got hot but the weapon did not fail, which is the important part.

quote:

Originally posted by Fourxfour:
Was there a difference with the Keymod?

The KeyMod handguard was also aluminum, and the one we were shooting on was the K model, so it was even shorter than the 8" (so it had even less surface area with which to radiate heat from). The material is probably the same composition of aluminum so I would guess that the rate of heat radiation is the same, all other things being equal (given equal sized handguards). Actually the KeyMod probably has less surface area since the KeyMod holes are bigger, thus resulting in less overall surface area from which to radiate heat.

Thank you for the great response!!! I can't wait for these to hit the market.

quote:

Originally posted by LDD:


I’d like to point out two curious additions in the upper receiver. The first an ovular plate, held in by two screws. We won’t get to go inside the MPX, but this sacrificial plate (like on the MCX) is our first clue that the MPX uses a rotating bolt with a cam pin. This plate takes the brunt of the punishment from the cam pin, preserving the integrity of the softer aluminum receiver. [We were able to see the bolt, but not take any photos of it. It looks like an AR BCG that’s had the back half of the carrier chopped off. The bolt has a rotating 5 lug head.] Below the sacrificial plate is a pinned-in convex piece of steel that functions as reinforcement for the chamber. Note that the display room version of the MCX does not have either of these features.

You know, in seeing the sacrificial plate being used it strikes me that SIG is pulling a page out of its own design history. I've got a bit of experience with the HK 9X series, and while the HK roller locked system was a reliable and durable system, it did depend on replacing the rollers with over-sized ones as wear occurred. After years of shooting the HK 9X I was then introduced to a SIG PE-57 (or AMT?) and once I saw the sacrificial receiver cups that were C clipped in place for their roller locked system, I saw the genius in the simplicity of the solution SIG used.

LDD, a few questions:

1) I can make out at least two notches on the A3 type twin tube sliding stock... but perhaps there is another that is not readily visible... is the sliding stock an open/closed affair or does it have an intermediate position? Also, what kind of latching/locking mechanism did the slider use?

2) What type of BUIS was SIG using on the samples you used and what were your impressions of them?

3) I realize you were most likely spending your precious one-on-one time analyzing the MPX and not the RDS... but any impressions of the SIG RDS?

quote:

Originally posted by Modern Day Savage:
LDD, a few questions:

1) I can make out at least two notches on the A3 type twin tube sliding stock... but perhaps there is another that is not readily visible... is the sliding stock an open/closed affair or does it have an intermediate position? Also, what kind of latching/locking mechanism did the slider use?

The A3 sliding type-stock has three positions: closed, intermediate (middle) and full-open. The locking mechanism on the slider is located in the part of the stock that attaches to the receiver and is a top-mounted button.

My critique for SIG (which I shared with them at SHOT) was that the locking mechanism, or rather the release button, should travel with the tail of the stock. That way it does not require two hands to open or collapse the stock. While the overall length of pull is not that much, the stock will lock in the intermediate position unless the release button is depressed. IIRC, the intermediate position was about 4" which means that, going from intermediate to full extension, most people will not have hands big enough to easily pull on the stock and depress the release at the same time with the same hand. Suffice to say, getting the stock from intermediate to full extension will take most people two hands to accomplish. That's one of the reasons why I am more of a fan of the Kate Moss folding stock seen on the MCX--you can go from closed to open with one hand. I would actually prefer the option of a two position on the A3 style retractable stock given the way that it opens. With the exception of use while wearing thick armor or inside a vehicle, I couldn't see a good reason for the intermediate position, but I also did not shoot it in the intermediate position. I won't write it off just yet, but my first impression of the middle position of the A3 slider was that it was more annoying than utilitarian.

While a tail-located release would have bypassed problems presented by the annoying middle position, the combination of both was at least to my initial impression, problematic.

It's not a bad stock, and it felt pretty solid compared to some HKA3s I've played with, but other than for looks, I've never really been a fan of this type of stock to begin with.

I can already see someone JB welding away the middle notches on their stock rails . The other work-around to this would be to "sling" the gun from the QD point in the stock tail. You use your support hand to depress the button and keep it depressed, keep your dominantly hand on the pistol grip while pushing the gun away from you: the tension from the sling holds the stock tail against your body as you push the receiver away (in effect, the "sling" is your third hand). This type of "sling" would be more like the combination of a lanyard and shoulder holster/rig--think executive suite-&-tie protection detail and not SWAT entry. [Yeah, I've probably thought about this just a little too much for my own good.]

SIG's answer to my critique of their release button placement was that the A3 slider was not meant for rapid deployment and that the folding stock would be more appropriate for that application. And I can see their point. SIG has two folders, one looks like an ACE stock (it uses a tube that is roughly the same diameter if not exactly the same diameter as an AR buffer tube) and the other is the Kate Moss stock.

SBRs will initially ship with the A3 style slider. Pistols will ship in two configurations: one with SBX on a folding tube, and one w/o any stock at all.

I actually checked advanced estimated pricing from a distributor: while the MPXc pricing hasn't been updated (and probably won't till BATFE rescinds their injunction against the MPXc), it does look like SIG is making good on their earlier comments that street price for the MPX pistol w/o stock attachment could be $1300...unless retailers get greedy (which they probably will, at least with the first wave of MPXs). The version with the SBX will be about $200-250 more. It does not appear the an MPX w/ SB15 will be a factory option, although swapping an SBX for an SB15 would be easy enough.

quote:

Originally posted by Modern Day Savage:
2) What type of BUIS was SIG using on the samples you used and what were your impressions of them?

I did not use the iron sights to guide the gun, although they were present on the sample guns. I did examine them and thought they were improved over previous generations of SIG sights I'd seen on early 516s. MPXs will ship with iron sights and may even ship with the SIGdot.

It was interesting to me that the K we shot had the SIG sights wereas the 8" had Magpul MBUS pros on them. The MBUS Pro have an advantage in that they folded flatter and don't require a front sight tool for adjustment. The SIG BUIS have the advantage that they are basically free as they come with the gun. Is it worth it for you to replace them with something else? I don't think it will be for most end-users--they are plenty functional, if not low-drag.

IIRC they are soft-detent-up/soft-detent-down. This is the same as the MBUS Pros.

For the most part, I think end users will wind up topping their MPXs off with red-dots so it may be largely irrelevant for the majority of purchasers (and will be even more so if SIG includes SIGdots with each MPX, which is something I heard as a possibility).

quote:

Originally posted by Modern Day Savage:
3) I realize you were most likely spending your precious one-on-one time analyzing the MPX and not the RDS... but any impressions of the SIG RDS?

The "SIGdots" that we shot with were mini-Aimpoint clones. They were adequate for the 50 yard bursts that we were taking, but we did not dunk or otherwise torture-test them.

I did not receive any information to the effect that the SIGdots had been improved or hardened over previous generations of SIGdot.

I am interested in the 8" pistol, but would like the keymod hand guards. How easy are they to add, or am I looking to wait till they are available later?

quote:

Originally posted by LDD:

quote:

Originally posted by Modern Day Savage:
LDD, a few questions:

1) I can make out at least two notches on the A3 type twin tube sliding stock... but perhaps there is another that is not readily visible... is the sliding stock an open/closed affair or does it have an intermediate position? Also, what kind of latching/locking mechanism did the slider use?

The A3 sliding type-stock has three positions: closed, intermediate (middle) and full-open. The locking mechanism on the slider is located in the part of the stock that attaches to the receiver and is a top-mounted button.

My critique for SIG (which I shared with them at SHOT) was that the locking mechanism, or rather the release button, should travel with the tail of the stock. That way it does not require two hands to open or collapse the stock. While the overall length of pull is not that much, the stock will lock in the intermediate position unless the release button is depressed. IIRC, the intermediate position was about 4" which means that, going from intermediate to full extension, most people will not have hands big enough to easily pull on the stock and depress the release at the same time with the same hand. Suffice to say, getting the stock from intermediate to full extension will take most people two hands to accomplish. That's one of the reasons why I am more of a fan of the Kate Moss folding stock seen on the MCX--you can go from closed to open with one hand. I would actually prefer the option of a two position on the A3 style retractable stock given the way that it opens. With the exception of use while wearing thick armor or inside a vehicle, I couldn't see a good reason for the intermediate position, but I also did not shoot it in the intermediate position. I won't write it off just yet, but my first impression of the middle position of the A3 slider was that it was more annoying than utilitarian.

While a tail-located release would have bypassed problems presented by the annoying middle position, the combination of both was at least to my initial impression, problematic.

It's not a bad stock, and it felt pretty solid compared to some HKA3s I've played with, but other than for looks, I've never really been a fan of this type of stock to begin with.

I can already see someone JB welding away the middle notches on their stock rails . The other work-around to this would be to "sling" the gun from the QD point in the stock tail. You use your support hand to depress the button and keep it depressed, keep your dominantly hand on the pistol grip while pushing the gun away from you: the tension from the sling holds the stock tail against your body as you push the receiver away (in effect, the "sling" is your third hand). This type of "sling" would be more like the combination of a lanyard and shoulder holster/rig--think executive suite-&-tie protection detail and not SWAT entry. [Yeah, I've probably thought about this just a little too much for my own good.]

SIG's answer to my critique of their release button placement was that the A3 slider was not meant for rapid deployment and that the folding stock would be more appropriate for that application. And I can see their point. SIG has two folders, one looks like an ACE stock (it uses a tube that is roughly the same diameter if not exactly the same diameter as an AR buffer tube) and the other is the Kate Moss stock.

SBRs will initially ship with the A3 style slider. Pistols will ship in two configurations: one with SBX on a folding tube, and one w/o any stock at all.

I see you and I are on the same page in regards to the A3 stock. My question regarding the A3 notches/ positions and the locking mechanism were related to how some of the executive protection details carried the MP5 A3 with the stock collapsed and lanyard (paracord) anchored for instant stock deployment.

I think many who have used the A3 type stock will agree that its design favors concealment and compactness at the expense of some "shootability".

Thank you for your excellent well thought out impressions!

quote:

Originally posted by IrishWind:
I am interested in the 8" pistol, but would like the keymod hand guards. How easy are they to add, or am I looking to wait till they are available later?

Unforunately, I did not see how Adam took the handguard of the MPX off, but he did not have any tools with him so I think it's part of the standard take-down process.

The accessories for the 8" are supposed to be out when the 8" pistol/sbr becomes available.