Why the Sig Sauer M17 ASP Won

Why the Sig Sauer M17 ASP Won

M17 4.5mm vs. M17 9mm – The Real World Test

By Dennis Adler

Yes, the final choice was mine, but it was the best choice among a field of excellent competitors and one of the rare instances where the CO2 model could actually go up against its centerfire counterpart. For a comparison test with the 9mm Sig Sauer M17, I wore a UTG tactical vest to carry one of the guns. Here I have the centerfire pistol in my right hand and the CO2 model in my left. A spare CO2 pellet magazine is also in the holster’s mag pouch. This is currently the only way to securely carry a spare CO2 pellet magazine for the M17.

Of all the new CO2 models introduced this year, why did the Sig Sauer M17 ASP rise to the top to be chosen as 2018’s Replica Air Pistol of the Year? The five distinct categories of comparison and the points system used left it tied with the Sig Sauer WE THE PEOPLE 1911 and Umarex Heckler & Koch USP, a solid three-way that was broken by the extra one point given to the M17 for Technology of Design. But there is more to the technology side than just a CO2 pellet magazine, which is definitely a game changer for blowback action pellet firing pistols; there is also the capability of the M17 to be an honest real world training substitute for the 9mm centerfire pistol.

One of the key elements of the M17 ASP is accurate size. Some air pistols come close, others are dead on, and this is one of them. The CO2 model fit two popular P320/M17 rigs from Galco, the S3H shoulder holster, and a TAC Slide belt holster, a combination of leather for the belt slide with an injection molded holster form fit for the P320. If the CO2 version was going to be a problem with any holster, this would be the one and it fit like the centerfire model.

Training with 100 percent matching air pistols has essentially been about learning proper gun handling skills, drawing techniques, re-holstering, repeated practice aiming and acquiring the target, and learning to reacquire the sights on a slide that is moving back and then forward with each shot, and understanding trigger designs and improving trigger control. But for the most part, in terms of real world training, the process ends when you pull the trigger and a .177 caliber steel BB travels down a smoothbore barrel to hit a target set out at an optimum range of 21 to 25 feet. That is a limitation the Sig Sauer P320 M17 ASP does not have, and this was another consideration in awarding the one remaining point to Technology of Design. But it represents more than the technology of a new design alone, but rather what that new design can allow the pistol to achieve.

You have to look closely until you recognize the differences, but the 9mm is on the left. The major tell is the extractor at the rear of the slide. And we wonder why Sig didn’t put a faux extractor on the CO2 model other than to help safely distinguish it from the centerfire pistol.

With the M17 ASP, the self-contained CO2 pellet magazine allows accurate magazine changes for training, it eliminates the need to stop and replace a CO2 cartridge in the grip frame, or swap out an empty stick magazine. It allows the same realism as has been achieved with BB models like the Sig Sauer WE THE PEOPLE and Umarex HK USP, among others, but with a rifled steel barrel sending a 4.5mm pellet downrange at sufficient velocity to extend training exercises from the limited distance of 21 feet to practical close quarter battle distances of 45 feet. How do I know this for certain? For an upcoming issue of Combat Handguns magazine I performed a one-on-one shooting drill with the M17 ASP against the 9mm U.S. Army MHS program M17 semiautomatic version of the Sig Sauer P320. Here is why the M17 ASP won this year’s Top Gun title.

More minor details to separate centerfire from CO2 are the absence of the serial number view port in the polymer frame (allowing a look through the frame at the serial number stamped on the fire control housing), an external extractor behind the ejection port, and there is a slightly different curve to the DAO trigger.

On the firing line

The 9mm M17 extended capacity magazine used for the military model holds 21 rounds, (the standard capacity magazine 17 rounds), the CO2 model, which copies the military extended capacity magazine design, holds 20 rounds. Since there is no means by which a chambered round can be added to the pellet model’s count, 20-shots is as close as you can get. The M17 ASP allows hands-on training with the exact feel and basic operation of the centerfire model, along with a respectable velocity with 4.5mm pellets of well over 350 fps. The CO2 model also has the advantage of complying, by design, with the military model’s use of ambidextrous thumb safeties. The M17 ASP is compatible with all military and civilian holsters designed for the P320. (Due to the CO2 magazine design it will not fit in all standard magazine pouches, and fits best in adjustable military mag pouches).

Looking over these two M17 models, the value of the CO2 version at right as a training pistol becomes very clear. It is a physical match in terms of handling, sighting, and general operation. At the cost of pennies per shot in comparison to 9mm ammunition, everything you learn with the M17 air pistol instructs in shooting the centerfire gun and at longer distances from the target than CO2 BB models can effectively reach with accuracy.

Field stripping a P320 or M17 is a very easy task. The CO2 version (top) disassemblies similarly though the barrel remains integral with the CO2 model’s fixed fire control system.

I shot an entire combat test at a minimum of 45 feet using Law Enforcement Targets cardboard B-27 silhouette targets. This provides a center mass area of 6×9 inches containing the 9, 10 and X rings. Any hits inside that area and the 8 ring score 5 points. Blowback action CO2 BB pistols are intended for shooting distances of 21 feet; pellet-firing models ideally for 10 meter target shooting. The M17 ASP is very good at this distance, but it also delivered accuracy at 45 feet comparable to the centerfire pistols for multiple shooting position training exercises.

While the two guns feel the same and, up until you pull the trigger, are as close to the same as possible for an air pistol, recoil from the 9mm model is something you cannot experience with CO2. The Sig Sauer M17 ASP does have a heavier blowback action than most CO2 models but nothing prepares you for the actual sound and feel of a 9mm pistol being fired, except firing it. The M17 ASP takes you all the way up to that point.

Shooting exercises

I ran several training drills with both the M17 9mm and M17 ASP back-to-back,  including drawing and firing (from a UTG tactical vest holster as well as two Galco rigs designed for the P320 M17); shooting short bursts from a kneeling position at right and left angles to the target (noted as RA and LA on the targets); I practiced reloads (I had a spare magazine from Sig Sauer; extra magazines will be available for sale shortly), I shot on the ground and rolling onto one side, I did moving shots across the target’s path and rapid firing (indicated by either RF or M on the target) and shooting from a Weaver stance directly at the center mass section of the target (indicated by circles with no other ID). All rounds were fired using a two handed hold. I expended two CO2 cartridges and the overall test consisted of 80 rounds and two B-27 targets. The ambient temperature for the field test was 49 degrees with no wind. I shot the pellet test with lightweight 5.25 gr. H&N Match Green alloy wadcutters to achieve maximum velocity (an average of 358 fps).

The Law Enforcement Targets B-27 silhouette is a heavy cardboard version of the paper B-27 targets used for training. Firing from fixed positions, to moving, kneeling at right and left angles to the target, and shooting laying on my side, I placed 40 shots on the target from the various shooting positions with about 50 percent inside the 9, 10 and X with the P320 M17 ASP.

Shooting the M17 ASP at 45 feet is pushing the accuracy with a blowback action pellet pistol but the Sig delivered hits that are equivalent to passing accuracy at that distance with a 9mm M17. I ran the same test with the centerfire M17 using Sig Sauer Elite Performance 115 gr. FMJ. When you compare the centerfire and CO2 models side-by-side and on the range running the same tests, the real advantage in using the CO2 pistol for training becomes clearly evident in the actual feel of the gun in the hand, sighting with the white dot sights, the slide movement and moderate felt recoil, and consistency of the DAO trigger pull, which is remarkably close in feel to the 9mm pistol. The only thing missing with the M17 ASP is the heavier recoil, a much louder bang and much more expensive 9mm ammo. The Sig Sauer air pistol passed in every category and I came away with a test target that placed at least 50 percent of the rounds fired within the 9, 10 and X from multiple shooting positions at 45 feet. You could not do this with even the best blowback action CO2 BB model. The windage was close to center (pulling slightly left) and elevation required aiming at the 9 ring to drop shots into the 10 and X. Most were fired at one- to three-second intervals except on rapid fire tests and double taps (DT on the target). After each specific test I circled and labeled each test group so additional shots could be easily distinguished. I then ran the same test with the 9mm M17 and had similar accuracy results for total rounds fired.

My results with the 9mm M17 at the same distances, running the same shooting drills from the same positions, produced very similar results. This wasn’t target shooting from a rest or a static position; this was shooting on the move and aiming for the target’s center mass. The P320 M17 ASP provided a good training session for just pennies compared to firing centerfire ammunition. Everything you do handling the ASP is muscle memory training for the centerfire model.

The Takeaway

The need for training guns, in Sig Sauer’s opinion, has become paramount as a cost effective alternative to centerfire models for basic handling and shooting skills. The M17 takes that philosophy to the next level, one that had previously only been achievable with either CO2 BB guns for handling and basic training exercises (using self contained CO2 BB magazines), or with Airsoft pistols and marking ammo for force on force training. The M17 ASP adds another alternative to practical, affordable training (not for force on force training); live fire with accuracy at actual defensive pistol distances! That is the final reason why the M17 ASP won Replica Air Pistol of the Year. This is going to be a tough act to follow in 2019.

A reminder about safety considerations

Blowback action airguns like the new Sig Sauer P320 M17 ASP deliver the look, feel and operation of their cartridge-firing counterparts. This is what air pistol enthusiasts have asked for, but we must all be diligent in our proper use and carrying of these highly accurate air pistols. At a glance if one of these guns is displayed in public (not on a target range or shooting on your own property), it can very easily be mistaken for a centerfire or rimfire pistol, even by law enforcement officers. Never brandish an airgun in public. Always, and I can never stress this enough, always treat an airgun as you would a cartridge gun. The same manual of operation and safety should always apply. Remember, we as air pistol enthusiasts, collectors, and sport shooters, bear the responsibility of ownership. This, too, is part of training with airguns and the airgun experience. 

10 thoughts on “Why the Sig Sauer M17 ASP Won

  1. I looked back over your various blog reports on the M17 ASP and found you left out a some of the field stripping capabilities. The M17 ASP user manual says the barrel can be removed for the purpose of clearing a jammed pellet. In the first picture, the red arrow points to a button that when pressed down will release the barrel to slide out of the action. Once the barrel is removed, the guide rod and spring can be removed.

    I discovered one other easy field strip action that is not covered in the user manual. The black barrel is actually an assembly of a barrel shroud containing the actual rifled barrel and a cap at the breech end of the barrel. The cap twists off allowing the rifled barrel to be removed from the black shroud. There is another spring inside that slides over the rifled barrel to maintain tension on the cap when assembled.


    • That is a maintenance feature of the gun in the event of a severely jammed pellet that I did not mention, as it is not part of the normal field stripping of the M17, but I am glad that you brought it up. This is another feature of the gun, like the rear sight mount you also discovered, that will be addressed in 2019 as Sig Sauer releases additional/optional upgrades to the M17 ASP. While an interchangeable sight/optics base will be the first item, as far as I know, there is also a possibility of barrel options since the barrel can be released and removed from the fire control housing.



    • Just a possibility for future options, nothing confirmed, but Sig has plans for the gun. It is a platform in more ways than some CO2 pistols. I have no idea exactly what Sig Sauer has planned for the M17 in 2019, but this is not a company that rests on its laurels.


      • Is there a possibility for a 0.22 caliber conversion for the M17 ASP? The barrel mounting hole in the action looks large enough to accommodate a 0.22 caliber barrel, but can the pellet clip be redesigned to work with 0.22 caliber pellets?


        • I would think that it is possible, the M17 is a modular design, but there is the question of whether or not a 12 gr. CO2 could send a .22 pellet downrange at a sufficient velocity to meet Sig’s standard of performance for the M17 ASP. This did not prove to be an issue with the Diana Chaser .22 reviewed earlier this year but the Chaser has a much longer barrel.


          • My only other question about a 0.22 caliber conversion would be the mechanism for advancing the pellet belt. That mechanism is currently set to advance the necessary distance for a 0.177 caliber pellet. Would that mechanism require adjustment to advance the pellet belt the proper distance for 0.22 caliber pellets? I think that without an adjustment, the belt advance mechanism would fail to properly align 0.22 caliber pellets with the end of the barrel.


  2. TheSig deserved to win for all the mentioned reasons. The only problem is that is a breakthrough only for this pistol. The integral co2 bb magazines was a breakthrough that crossed over to many other designs of pistols. Ppk, P08, 1911, Mauser 712 and others. This design will not . It is for large grip non flush mount only. It is better carried over to Carbine configuration. The next major breakthrough will be a co2 bb mag type design that can feed pellets .




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