Sig Sauer’s new M17 Part 1

Sig Sauer’s new M17 Part 1 Part 2 Part 3 Part 4

The P320 in military dress

By Dennis Adler

This is where the history of blowback action CO2 air pistols begins to change. Sig Sauer has not only stepped over the threshold of a door that no one had opened before, they also built the door. The M17 could be a game changer for the future of blowback action 4.5mm pellet-firing pistols and that’s a lot to say in an opening statement, but I have had my hands on this pistol for over a month waiting to tell its story. We begin with the P320.

Is this a 100 percent understudy to the centerfire M17? Not entirely, even Sig Sauer, which appears to be able to design and manufacture new airguns at an impressive rate, can’t change the physics of a pellet-loading semi-auto, even one with an integral 20-shot rotary magazine and CO2 loading system. And it still comes in the unusual but sturdy Sig Sauer packaging which gives the gun plenty of storage protection.

The Sig Sauer P320 ASP is a full-size duplicate of the P320 Nitron centerfire version, left, which is one of the P320 configurations I had tested for Combat Handguns. The CO2 model has a full length dustcover accessory rail to mount lights and light laser combinations for training practice, but comes with the compromises that have been corrected for the most part in the new M17 ASP.

The Sig Sauer P320 CO2 model was introduced in 2017 and was not the epiphany in pellet-firing blowback action CO2 models air gunners were hoping for. But I have a somewhat different perspective on the P320 CO2 model than most, having tested and evaluated the centerfire P320 modular handgun system that evolved into the M17 back in 2016. I knew that when Sig Sauer got into the airgun manufacturing business to build training guns that it could never be the equal of a P320; yes some airguns are the BB-firing version of their centerfire counterparts, including the Sig Sauer WE THE PEOPLE 1911, but when you are talking a pellet-firing semi-auto, you are not going to achieve the same goal, at least not for the price of most blowback action CO2 models. There had to be compromises and Sig Sauer chose wisely for the most part developing a P320 CO2 model that could serve the basic needs of the design for training and still be an enjoyable and affordable recreational air pistol. Not everyone will agree with me on this but the P320 was a means to an end, a stepping stone for a company that moves quickly.

The most interesting feature of the Sig Sauer P320 ASP was the introduction of a belt fed pistol magazine for the blowback action, rifled barrel pellet pistol. It was a big step forward and laid the groundwork for the more innovative self-contained magazine for the M17.

What were the biggest complaints with the P320 CO2 model? It wasn’t size, or handling, certainly not velocity or accuracy at 10 meters (I have shot it accurately out to 45 feet), it was with the separate CO2 loading system in the pistol grip and an incredible misunderstanding of the rotary magazine system. The P320 was a very big step forward from traditional 8 shot pellet magazines or reversible 8+8 magazines. Another complaint and one I agree with was the lack of a separate slide and barrel lug interface which was carried over from the P226 ASP. Negative features versus plusses, it was a very short list but Sig Sauer designers knew the P320 ASP was not the end game. By the time the CO2 model came out Sig Sauer’s centerfire P320 had already won the U.S. Army Modular Handgun contract to replace the military’s aging Beretta 92 service pistols. It was almost a fait accompli because the fundamental structure of the MHS was a handgun that used a modular design that could be easily changed from one configuration (slide, grip, frame, and caliber), to another using one contiguous fire control housing. That was the design of the P320 introduced in 2014. It was Sig’s first polymer frame, striker-fired model and it already met the basic MHS requirement. The final military version added some specific modifications and adaptations to military needs, including extended capacity magazines and ambidextrous thumb safeties.

There is a definite similarity between the P320 ASP and the M17 ASP but the improvements have clearly eliminated several of the objections to the first blowback action models including the trigger contours, and lack of an actual slide and barrel lug interface, which became very obvious on the Coyote Tan P320 ASP.

The P320 ASP CO2 model came in either black or Coyote Tan while the P320-based M17 comes in a variation of the Coyote Tan P320 finish matching the military version. The P320’s silhouette, basic operation and Coyote Tan color, however, is about all the new M17 CO2 model has in common with the P320 ASP.

The new M17 has most of its parts working including the manual safety designated for the military versions. Also note the actual slide and barrel lug interface that separate when the slide moves back during recoil and chambering of the next round.

From an overhead view the new M17 has a very realistic look. When the slide comes back you get a look at the inside of the firing mechanism which is quite different from other blowback action air pistols. We’ll examine this in Part 2.

The nextGen Sig Sauer Air Pistol 

If we look at the P320 as a starting point, in less than two calendar years Sig Sauer has again introduced a completely new air pistol that not only matches its centerfire military and civilian M17 counterparts but assuages two of the greatest issues with the first P320 CO2 model, a self-contained CO2 pellet magazine and a realistic looking slide and blowback action. The gun promises hands-on training with an authentic look, a velocity with 4.5mm pellets of up to 430 fps, and unrivaled handling and accuracy and while the magazine release may not be ambidextrous, the manual thumb safeties are.

For what its worth, the P320 in Coyote Tan is a good looking air pistol that provides reasonable hands-on training for the P320 but lacks the key features that have been incorporated in the slightly more expensive M17 which is a very close match to the military version with its extended capacity magazine. As training guns go, Sig has nailed this one for the military and civilian market. There are a couple of “quirks” which will be covered in upcoming articles, but these compromises to achieve the goal of a self-contained CO2 pellet magazine at first glance seem to be worth it.

In Part 2 we begin to unbox the P320 M17 and see what Sig Sauer has done to the world of blowback action CO2 pellet pistols.

14 thoughts on “Sig Sauer’s new M17 Part 1

  1. Seems SIG is using each model as a stepping stone , not a headstone. If thismag system works it is a game changer. For certain pistols it may mean reduced magazine capacity to fit flush , but where it could be a new standard is in Carbines like some from Sig , and H&K. Dual co2 , 30 rounds , select fire . If Umarex wants to compete they should offer a select fire 712 pellet model using this type of mag , and maybe a Beretta 93r , Grease gun , and the holy grail , 30 round pellet firing Thompson.


    • Being a Broomhandle Mauser fan that would be my personal choice for a Sig-like system to fire pellets from a rifled barrel. That would make the M712 the best blowback action CO2 pistol on the planet. Are you listening Umarex?


      • Kind of doubt Umarex is listening, or we would have 4 3/4 & 3 1/2 barrel Peacemakers. Will probably fall to another company , most likely Sig , to implement the Carbine select fire variant.



  2. Since I started this,I would suggest following to Umarex if they really want to offer a true Heritage series of select airguns using this new style magazine ,I would add the following to those mentioned. SW43/44, British Sten, M2 Carbine.


    • It is all good except the magazine technology isn’t Umarex it is Sig Sauer’s and it may well be a proprietary design, so other airgun manufacturers could not copy it. This does leave that door wide open for Sig to do some remarkable things, however.


      • I doubt Sig will authorize its’ design but others should come out with something similar . For awhile I have advocated a Thompson 50 round drum fed by an internal belt , with several 12 gr cartridges in a star cluster feeding the gas system. That system could be used in a AK , AR SAW, and a smaller version for Luger snail drum. Just saying. All that is neede is thewill and a dedicated company


  3. All this talk about select fire made me select a select fire MP40 and send some steel doenrange around 25 feet , burst fire . A rifled barrel pellet version should do this or better past 30 feet.


  4. I would prefer a BB version. I get too many blocked barrels with my CO2 pellet pistols and rifles although alas in the UK we cannot select “auto” on an MP40. However can you imagine how quickly the barrel would block up!!



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