Semi-auto pellet pistol evolution

Semi-auto pellet pistol evolution

From perfection to perfection

By Dennis Adler

Sig Sauer designed the M17 CO2 pistol and it is an actual Sig Sauer product, not a licensed design for another company to build and sell, but, unlike the Beretta 92FS, which is still made in Germany, the M17 is built for Sig Sauer in Japan. That, combined with a less expensive to produce polymer frame and integrated grips, as opposed to a cast alloy frame with wood grips, makes the 92FS more expensive to build no matter where it is manufactured.

It was just 23 years ago that Umarex introduced the first semi-auto style pellet pistol, the Walther CP-88. It is still manufactured. In 1999, Umarex developed its second semi-auto style pellet pistol, the Beretta 92FS, which was introduced at the turn of the new century, becoming what remains, 19 years later, the best built CO2 pistol of its kind, still handcrafted and manufactured in Germany. Two remarkable guns that launched a generation of rotary magazine semiautomatic pellet pistols, but were they true semi-autos? The answer then and now is no. The Umarex Beretta 92FS looks, feels, and handles like its centerfire Beretta counterpart but its internal operation is that of a revolver with the cast alloy 8-round rotary magazine turned from chamber to chamber by pulling the trigger. It was a beautiful deception.

A semi-auto on the outside, but with a flick of the disassembly lever the slide separates and reveals the rotary magazine chamber. The slide release was non-functional, there was no blowback action, the ambidextrous safety did work and the gun could be manually cocked and de-cocked. Combined with superb construction, fit and finish and real checkered Beretta medallion hardwood grips, this was as good as it got 19 years ago. Of course, Umarex had already broken this ground in 1996 with the Walther CP-88, but the Beretta was a better looking gun.

And generations followed

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The concept pioneered with the CP-88 and 92FS continues to this day, it is a design that works, is reliable, and allows a CO2 pistol to shoot lead pellets through a rifled barrel with precision accuracy. While the majority of air pistols built today using this system, like the Umarex Beretta PX4 Storm, are either built in Japan or Taiwan, in its day, a generation ago, the “Made in Germany” models were the foundation for using CO2 pistols as training guns; the 9mm Walther P-88 and Beretta 92FS and then the Walther P99 were at the time, among the most popular handguns in the world, in use by law enforcement and military.

And thus it began with an 8-shot rotary pellet magazine. The irony of this image is that the gun that started it all when there were only lead pellets, can also load the very latest alloy pellets made by number one competitor Sig Sauer.

For all intents and purposes these CO2 copies were the best multi-shot pellet-firing air pistols you could own for quality of construction, fit, and exceptional finish.  And in all honesty they have never been surpassed in that respect, since many of even the finest new models, like the centerfire guns they are based upon, use polymer frames, which were introduced by the Umarex Walther CP99. Still the technology of the rotary magazine, even when updated with 8+8 rotary stick magazines in guns like the Umarex Beretta PX4 Storm were still revolvers at their core.

It took until 2017 for anyone to find a better way to load pellets into a pistol than either 8-shot or reversible 8+8 shot rotary stick magazines. Sig Sauer innovated the loading process with a rotary stick magazine that allowed the 30-shot (later reduced to 20-shot) stick magazine to operate in a blowback action CO2 pistol. Sig took a lot of liberties with the design though, making most of the controls inoperative, except for the safety, as they served no function on the pistol. It could not lock back on an empty magazine so Sig saw no reason to have a functioning slide release, or to cut an actual ejection port into the slide. As well priced as the polymer-framed pistol was, the cost-saving measures Sig Sauer took with the P320 ASP turned more than a few potential buyers away. But at the time no one knew what Sig Sauer was developing for its next P320 air pistol.

But technology finally overtook them in the last year and of all the airgun manufacturers in the world that could have done it, it was a company that had only started designing and offering their own brand of air pistols in 2016, Sig Sauer. The P320, introduced in 2017, became the first rifled-barrel, pellet-firing semi-auto pistol that was, in its operation, a true magazine-fed semiautomatic and not an internalized revolver.

The second drawback to the P320 ASP was that Sig Sauer had resorted to a very conventional and slow method of loading the CO2, actually taking a step back from the earlier P226 ASP which had used an 8+8 rotary stick magazine. This, too, confused the market. But again, no one knew what was coming the next year from Sig Sauer.

Sig’s technology is as yet unchallenged by other air pistol manufacturers, but has this new higher level of authenticity surpassed the original rifled barrel semi-auto style pellet pistols? To find out, the very latest example, the Sig Sauer M17, with a 20-round self-contained CO2 pellet magazine, goes head-to-head with the best of the original multi-shot pellet pistols, the Umarex Beretta 92FS. It is not only a comparison of airgun designs but a comparison of handgun evolution.

What you get from different technology

We begin with the Beretta and how this German-crafted airgun is put together for its suggested retail price of $300 with nickel finish and real hardwood Beretta grips. This is the way things were done in the 1990s when realistic-looking air pistols were few in number and Umarex built them is Germany. And the 8-shot rotary pellet magazine was the new technology. In 20-year old dollar values, the Beretta was top price for quality at $258 in nickel with wood grips when it came out.

Going back almost 20 years when you look at the Umarex Beretta 92FS you see an all metal gun with a striking fit and finish that is still handcrafted in Germany. Price has its privileges even if the gun is outmoded by the M17 CO2 model. And for the most part everyone agrees the same goes for the 9mm P320 M17 vs. the Beretta 92FS M9 military guns.

At 2 pounds, 15 ounces, the 92FS air pistol remains a hand-filling gun that was scaled to the dimensions of the 9mm 92FS. Where Umarex cut the smallest corner was in not having the optional (for the 9mm model) white dot sights. For holstering, drawing, sighting and firing the first shot double action, the CO2 pistol delivered the accurate feel right up until you pulled the trigger. Then it was a soft report and no recoil. The slide didn’t move and the gun stayed solid in the hand like a single shot target pistol. It was all show and accuracy, and little more in terms of actually handling a centerfire Beretta 92FS. It was good enough for the time and despite all the technology that has followed, still good enough to remain one of the best selling multi-shot pellet pistols in the world almost 20 years later.

Time and technology will win out

That is not always a given. Simple solutions to operation for the 92FS were to locate the CO2 into the pistol grip (by removing the right side grip panel) and incorporate a built-in seating screw and piercing mechanism in the base of the grip frame. This system is still used on a number of much newer CO2 models, including the Sig Sauer P320, which, while it improved the operation, remained the same idea; two separate procedures for loading the pellets and CO2.

To use the word “groundbreaking” for the P320 M17 ASP is diminishing what the company achieved in three steps from the P226 ASP to P320 ASP to the M17 ASP. Here was almost everything blowback action air pistol enthusiasts had been begging for in a pellet-firing semi-auto. Almost, because even Sig Sauer couldn’t find a practical way to make a pellet-firing semiautomatic with a slide that could lock back on an empty magazine.

The breakthrough of incorporating the CO2 and the pellets into a single magazine was not a solution anyone had worked out until last year when Sig Sauer developed the P320 M17 CO2 model. This third solution to increasing pellet capacity from 8 to 16 and then to 20, had also achieved a means of creating a self-contained CO2 pellet magazine. Using a two-piece design, the M17 magazine holds a 20-round pellet clip and CO2 in one.

The evolution of the P320 ASP rotary pellet magazine from 2017 to the magazine portion of the 2018 M17 self-contained CO2 pellet magazine was about as fast as an idea can go from concept to production.
The pellet clip locks into the CO2 magazine (which loads the CO2 in one step) to form a self-contained magazine that allows reloading at the speed of a centerfire pistol. For BB guns, no big deal, for a pellet-firing pistol, the most totally innovative gun since the Umarex Walther CP-88 and Beretta 92FS.

And thus we arrive at the greatest total number of improvements from the first Beretta 92FS pellet model to the innovative Sig Sauer M17; a near 20-year journey. But, along the way, blowback action was also developed for pellet pistols like the Beretta PX4 Storm and the Sig Sauer P226 (and P250) designs. Essentially Sig rendered the 8+8 rotary stick magazine obsolete with the P320, but still with separate CO2 and pellets.

The M17 CO2 model almost duplicates the centerfire guns with some very minor exceptions. There is no serial number window in the frame (the serial number plate is on the fire control housing inside the frame), the trigger contour is slightly different, and of course, there are no molded-in warnings on the frame and the guns are not marked made in Japan.

The M17 in turn makes the P320 obsolete in that same respect. We have before us the two ends of the design spectrum, the 92FS and the M17. The question that needs to be asked now is “will the M17 (like the Beretta 92FS pellet model) still be in production 20 years from now?”

Another thing that time changed as prices for air pistols, pellet-firing air pistols in particular, came down was the level of packaging with the gun. Back in the day of the Umarex Beretta 92FS, a hard plastic, fitted Beretta carrying case, with two rotary magazines and a wrench to loosen the set screw and adjust the rear sight for windage, was standard practice.
Today the Sig Sauer M17 ASP comes in a reusable package that serves to display the gun and allow for storage in a molded two-piece clear plastic liner. This is better than a blister pack by leaps and bounds. But for a retail price of only $139.99 you’re not getting a hard case equivalent to usual centerfire Sig Sauer cases. On the bright side, the M17 centerfire guns for the military come in a cardboard box.

In Part 2 we see if technology can create a gun that will outshoot an established design.

14 thoughts on “Semi-auto pellet pistol evolution”

  1. I wouldn’t go so far to say the P320 is obsolete. As someone who uses this platform for plinking, the P320 is a great ‘grab and go’ plinker. Because it’s basically stick fed, I can bring two extra magazines and go plinking outdoors and shoot out an entire c02 cartridge without having to reload pellets outdoors. This can be very convenient. Also the lack of moving parts makes it very simple to use with little to go wrong (I always recommend light pellets with this pistol however). For training it is indeed outshined but for a blowback pellet plinker it gets a lot right. Just a different perspective for its lack of features.

    On a different note, are there any recommendations for making my Dan Wesson 712 a carbine? I have the 6″ pellet version.

    • My use of “obsolete” was in terms of technology, the P320 design still works great, and as you say, the thin 20-round stick pellet magazines are very easy to carry. In point of fact, your comment about “the lack of moving parts makes it very simple to use with little to go wrong” underscores Sig Sauer’s intent with the early models. The M17 ASP raises the bar but with it come more moving parts and a larger magazine to carry. The M17 is a more exciting air pistol to shoot, but I didn’t mean the P320 ASP was not a good gun, it certainly is.

      As for the DW, I am not aware of any way to mount a shoulder stock like the Umarex S&W.

    • Steven, I have to agree in that they are not semi-autos in any real sense, but I like to think of the advanced system Sig Sauer has developed as comparing a Webley-Fosbery to a Colt Peacemaker; almost a semi-auto. And of course, belt-fed machine guns have some role in what Sig Sauer engineered for the P320 and M17 blowback action pistols. It is more illusion than fact but you have to love the concept.


      • I must strongly disagree.
        The Webley-Fosbery advances the cylinder by recoil, not by trigger pull. This makes it a semi-automatic revolver. Which is what sig should have done, at least their marketing would be less deceptive.

        The sig pellet guns are just double action revolvers the same as any other. No wishing will make it otherwise, they aren’t almost anything.

        The concept is fine, the advertising is fraud. It is intentionally deceptive and frankly Pyramydair has been going along with it. If any retailer would push back on these practices they would earn my business.

        • I guess we could debate this ad nauseam but you are right that it is like a revolver, in that the mechanism designed by Sig Sauer to work in conjunction with the 20-round rotary pellet magazine in the M17 is, in fact, actuated by the trigger and not the blowback action. However, it is an innovative approach that uses two hands that extend into the front of the magazine as the trigger begins its rearward movement. One hand locks the magazine in place while the other advances one chamber in the rotary mechanism. This happens in one stroke as the trigger comes back to actuate the CO2 firing mechanism. This is a different design than a typical 8-shot rotary magazine that fits over a spindle like the arbor or cylinder pin in a revolver, and has ratchets that are engaged to rotate the pellet cylinder as the trigger is pulled, exactly like a double action or single action revolver, the latter with the hammer being cocked, which is what happens when you cock the hammer on the Umarex Beretta 92FS instead of firing it double action. But I am sure you know this or we wouldn’t be having this discussion in the first place. Are we belaboring an issue here, most definitely, my point being that the M17 (P320) design is new and moves the concept of a semi-auto pellet pistol one step closer to an actual semi-auto design. Is it an internal double action revolver? No, not in a conventional sense. Is it a functional semi-auto? No. It is a new design that works better and faster than any pervious type of multi-shot pellet-firing pistol. The only way a real semi-auto will be possible is to design a means of stacking pellets in a self-contained CO2 magazine using an actual follower, like current blowback action CO2 BB pistols. The problem has always been the fragility of lead pellets to deforming under stacked pressure, and of course, their shape. Could you shoot round lead balls in this configuration in a stacked magazine? Very likely, but the accuracy of a wadcutter down a rifled barrel vs. a round lead pellet would not be the same. At some point Sig Sauer or Umarex or some other manufacturer will find the solution to having a real semi-auto pellet pistol that allows the pellet to advance up a stacked column like a cartridge pistol. Until then, the M17 sets the bar. I do not view the design or its representation as a semi-auto as fraud or deception. As a gun guy, which you obviously are from the conversation, you really should give one of these a try, you’ll be impressed.

          • If the recoil of the slide or the gas somehow moved the belt, I would be with you on this. That would be a belt fed semi-auto. As they are now it is intentionally deceptive. Otherwise no one would have to ask if the trigger advanced the belt or not.

            Stacking pellets in a magazine has a few obvious solutions. One is to use Sig’s, really h&n, lead free pellets. The other is casings, to change the outer profile to be like cartridges.

            I would love to own one of these, but the misleading advertising is keeping me away. I almost caved last night, but I just can’t in good conscience.

            I want to thank you for not deleting my post on this topic. I really appreciate that.

  2. Steven, this is what the comments section is for, to voice opinions and begin discussions, I don’t delete comments, I discuss them, especially when someone makes a valid point as you have done. We do, however, need to acknowledge technology that moves the bar and brings this one segment of the air pistol market a step closer to attaining with pellet-firing semi-auto designs that which the higher-end BB-firing semi-autos have achieved. I don’t think anyone who likes the modern design of the M17, its operation, use of more accurate pellets over steel BBs, and the pistol’s authentic handling, should deny themselves the experience of owning one on a technicality over exactly how it operates. It’s a darn good airgun and we are airgun enthusiasts or none of us would be reading Airgun Experience, nor would I be writing it. Thanks for being part of the conversation.


    • Dennis,
      The technicality of the operation does not bother me one bit. The misleading marketing is what bothers me. I hate to think my hard earned dollars are going to pay to promote this borderline fraudulent advertising.

      If Sig tomorrow announced a total ban on calling it semi-auto and that they would enforce this against the media as well, I would have one ordered before the end of the day.

      It is only the misleading advertising that makes me refrain from buying one. Between you and me, my desire to own one will likely get the better of me soon enough.

  3. Steven, sounds like you’re coming around, but your point is still well taken. The terminology, as it has been explained to me by Sig Sauer on a recent phone call following your first comment, is that they regard the operation as semi-automatic for an air pistol because of the unique design of the pellet-firing mechanism overall. It is different in a number of ways including the means by which the CO2 in the magazine connects with the fire control housing permanently fixed in the polymer frame. When you remove the magazine, for example, you get an air burst sound not unlike removing an attachment from an air compressor hose. The system tied to the trigger to rotate the pellets in the magazine is also unlike any before, and yes, it is semantics about the term “semi-auto” as it applies directly to the trigger’s relation to the magazine rotating system, but the trigger’s involvement in the movement is so subtle and brief as the trigger comes back, that it adds virtually nothing to trigger pull resistance, as opposed to a double action revolver’s mechanism, such as used in the old 92FS. There is no real comparison. But as you say, it is not rotated by the reaction of firing the M17 ASP like an actual centerfire semi-auto. I think everyone agrees on that. Overall, I think the gun earns a pass when you compare it to anything else on the market.

  4. I appreciate Mr. Adler using old style playing cards without indexes for targets of replica guns of the 1800’s. The most common brand is Highlander 1864 and they sell all over the net for about $9 to $13.

    But has them for $4.98 a pack and free shipping for orders over $50.
    So 11 packs is $54.78 = $4.98 a pack total.
    Buying less than 11 packs incurs a very steep $8.98 shipping charge.

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