SIG 716, SIG MCX and SIG 556 Xi: An Afternoon Of New Rifles At The SIG Academy

When we arrived at the SIG Academy and saw all of the stacked hard rifle cases at our range we had a pretty good idea this was going to be a fun and informative afternoon. We weren’t wrong either! There were suppressed MCX multi caliber carbines, the SIG 556 Xi, the SIG MCX and the SIG 716. Several of the models were in a pistol configuration using the SIG SB15 arm brace.

SIG_SAUER_SIG_MCX_Multi-Caliber_AR_Assault_Rifle_Carbine_SBR_300_Blackout_300BLK_Suppressed_Kevin_Brittingham_Thumbs_Up_and_Smiling_SIG_SAUER_New_Media_Writers_Event_David_Crane_DefenseReview.com_DR_1-660x330 (1) copy

Photo by David Crane

Before I start with the various rifles let me introduce Kevin Brittingham. Kevin is standing to my right in the photo above. Kevin is a pivotal figure in the story of many of the rifles we fired that afternoon. For those that don’t know, Kevin is the founder and former owner of AAC. He sold AAC to Remington and now works for SIG designing and developing suppressors and features of the guns that use them. Kevin is also the creator of the AAC Honey Badger.

In the photo I am holding the suppressed SIG MCX which we had just fired. This MCX is chambered in 300 Blackout. You’ll note the suppressor has no finish on it. This is because it was put together and brought straight to the range from the factory. The factory did not have enough time to apply a finish. You are probably wondering why Kevin has such a big smile. I had just told him this was the quietest centerfire rifle I’d ever shot! Naturally he was happy to hear that. At 118 decibels he has a right to be happy.

In this video I am firing the SIG MCX with super-sonic ammo (it obviously makes the gun much louder than firing sub-sonic ammo).

This time firing sub-sonic ammo:

The MCX is a multi-caliber carbine firing the 5.56, 300 Blackout and 7.62×39. Caliber changes can be made in the field in a very short time. The suppressor is the screw on variety. There are three buttstock designs. There is a standard M4-style stock, an MP5-style stock and a third design, which I was firing called the SAS. The final complete specifications for the MCX are not yet available.

The next model we shot was the SIG 716 pistol in 7.62×51. Now this pistol was fun to shoot but I could not really get excited about firing it as a pistol.  I did find it comfortable to shoot using the brace as a stock but it does have a bit more recoil than your standard .308 rifle.

Firing the SIG 716:

Then we have the one and only writer willing to continue shooting the 716 using the SIG brace.

Sig 716 in 7.62x51

SIG 716 in 7.62×51


Action Semi-Auto
Operating System
Short stroke pushrod, rotating Bolt
7.62 X 51 mm NATO
38.3 in – 31.1 in / 972.8 mm – 789.9 mm
Trigger Type
Trigger Weight
7.6 lbs
Barrel Length
16 in / 457.2 mm
1 in 10″
Number of grooves
w/out Mag 9.3 lbs / 4.22 kg
Mag Capacity
20 Rounds
Mag Type
Magpul PMAG
Accessory Rail
Short stroke pushrod operating system with 4 position gas valve, Quick-Detachable Ambi-Sling Mounts, Flip-Up Front and Rear Iron Sights, Ambidextrous Magazine Release

The last rifle is the SIG 556 Xi Russian chambered in 7.62×39. It is also available chambered in 5.56mm and 300 Blackout.

Firing the SIG 556 Xi in 7.62×39:


Caliber 5.56mm NATO
Overall Length 35.875″
Length w/Stock Folded 27.1″
Barrel Length 16″
Rifling 1 in 7″
Sight Radius 18.1″
Forearm Polymer
Stock Type Swiss folding
Weight w/o Mag 8.2 lbs
Operating System Gas Operated, Rotating Bolt
Mag Capacity 30 Rounds
Features Rotary Diopter Sight
MSRP $1,266.00
CA Compliant No
MA, NJ, NY, CT Compliant No

At the end of the day it was time to blow off some steam by doing some building clearing exercises with simunition rounds.

I have to say the several days spent with the folks at SIG was a great learning experience. It is my sincere hope that the articles I’ve presented to the readers have been informative and enjoyable. If there is any information you would like which has not been presented in these articles feel free to contact me in the comments below and I will try to answer your questions.

Late News From SIG:

I just recieved an email from SIG announcing a micro website that will allow readers to peruse the new model rifles as well as the SIG 320 pistol. You’ll be able to click on each gun and see what options are available as well as how they look on the gun you choose.

As you know, there’s a lot to take in, option wise, with each firearm. Here’s a handy guide showing all the innovation and tech that went into each product, as well as a breakdown of the options. So, if there was any confusion about a SIG MPX vs a SIG MPX-K or SIG556xi Russian vs SIG556xi Carbon Fiber… or any number of combinations…. Here’s a tool to help figure it all out. Plus, it’s just cool to see all the parts.

SIG Evolution Website

Screenshot of the new SIG micro website

Screenshot of the new SIG micro website

Phil White

Retired police officer with 30 years of service. Firearms instructor and SRU team member. I still instruct with local agencies. My daily carry pistol is the tried and true 1911. I’m the Associate Editor and moderator at TFB. I really enjoy answering readers questions and comments. We can all learn from each other about our favorite hobby!


  • Toms

    When is the MCX and 7.62xi going to be released to the public?

    • SIG tells me the new rifles will be released in October-November at latest. Of course as with many new gun releases some calibers come later. I don’t expect this one to be later though.

  • dp

    The XI looks as most interesting from military point of view. I does swap between calibres and as I understand parts replacement is quit swift. How about LSW version with open breech fire; do they plan for that?

    • No as far as I know that’s not in the works. Of course the military projects tend to be confidential a lot of times so they may have something in the works we may not hear about for some time.

      • dp

        Thanks Phil; that was just for curiosity. I know that focus here are sporting arms or at least sporting versions.

        • No big deal DP. I’m as interested to know what military applications will come from these as you are. There almost has to be you would think.

  • Jeff S

    How much is a barrel/bolt swap going to cost for the xi?

    • That we don’t know yet. Some of the extras as still so new there haven’t had prices determined yet. I can call and check they may have an idea. Just let me know.

      • Jeff S

        Not a big deal… The reason I ask is because I actually saw a 9mm Tavor swap and it was almost $1k. I was just curious as too see how outlandish the SIG prices would be.

  • Jeff Smith

    Oh, the burdens of being a writer for the Firearms Blog! Hahaha!

    Great article, Phil!

  • echelon

    Sig, in my mind, is on the vanguard of pushing the envelope of firearms technology in the 21st century. Really glad to see them embracing short barreled models with braces for their new designs!

    Now the key is to make sure they follow through on having parts availability and keeping the prices competitive with established guns like AR15s and such.

  • Seburo

    So no news on the SG 750? If it’s anything like it’s smaller cousin it would give the FN other .308/7.62 Nato semi autos a run for for their money.

  • Marc

    Why no mention of the pictured SSG3000? It’s a fantastic rifle that gives even higher priced rifles a run for their money.

    • We were actually supposed to shoot it at 1000 yards. We had a conflict of range time with the Mexican Navy who were also there. No I’m not kidding it was the Mexican Navy.
      Anyway that kept us from shooting it.

  • Patrick Mingle

    Will LE departments really ditch their ARs for any of these platforms though?

  • Stan Darsh

    Speaking of the Sig MCX/Honey Badger, Does any of our Canadian brothers happen to know what kind of difficulty is involved in importing a rifle buttstock from Canada to a citizen in America? Would it be better to have an importer like ATI get these imported ?

    • Rusty Shackleford

      Hopefully Paladin will answer you sooner, but I’ve sent an email to them and their American counterpart to see.

      • ATman

        being not an actual firearm it might not be that difficult there are a few firms that do both import and export across the US and Canadian borders.

  • Rusty Shackleford

    The SIg 716 and SIG 750 sound like a nice purchase. I’m curious if Sig has gotten their QA/QC in check after the problems with SIG USA built rifles over the last few years.

    • I’m not aware of any problems now. In fact I’ve heard nothing in a couple of years.

      • Rusty Shackleford

        That is good to her. Puts my mind at ease about making the purchase, thanks.

  • Seth Hill

    I’ve always wanted one of their original 556 (classic or patrol), I was mad that they replaced them with the proprietary magazine version. How is the new 556 compared to the old one? Does the new one use AR mags?

    • Tucson_Jim

      The SIG 556 Classic was never “replaced” by the SIG 551 A1, both are based on the Swiss Arms SG 551 LB carbine (which is based on the SG 550… which is a redesign of the AK-47 that was optimized for the Pat 90 cartridge) with the SIG 556 Classic having the STANAG-compatible lower receiver, and the A1 having the rock-n-lock Swiss magazines (which can also be locked together).

      Many militaries prefer the rock-n-lock magazines’ more accurate/reliable feeding to the drop-free STANAG style. The battle-proven M14, FAL, CETME, AK and SG550 all have r-n-l mags.

      To resolve the continual disagreement over whether an AK-47 is better than an M16… the Swiss designed the SG550 better than both.

  • TheSmellofNapalm

    With regard to the sig evolution video on the xi: Most of us saw very similar marketing, mission statements and graphics for the Masada/ACR. In many ways the concepts are incredibly similar. I only hope that the future of this rifle is more successful