P320 ASP Part 3

Sig Sauer’s 4.5mm P320 ASP Part 3 Part 2 Part 1

Training practice and 10 Meter accuracy tests

Shop Benjamin Rifles

By Dennis Adler

The new Sig Sauer P320 ASP is a full-size duplicate of the P320 Nitron version. The CO2 model has a full length dustcover accessory rail to mount lights and light laser combinations for training practice.

Back in 2000 when Walther and Umarex introduced the CP99 pellet-firing model, it was as physically close to the 9mm P99 as possible (for the times and available technology for semi-auto air pistols). The very first blowback action CO2 model, the Walther PPK/S, was also introduced that year, so in terms of advancements in design, technology, operating systems, and model variety, the airgun industry has grown in leaps and bounds over the last 17 years. The new Sig Sauer P320 ASP represents another of those advances being the first high-capacity, blowback action semi-auto pellet-firing pistol.

Loading the 30-round rotary magazine is a snap, just open the loading cover (which exposes the majority of pellet loading loops), press a 4.5mm wadcutter pellet into each loop, carefully rotating the belt until all loops are loaded. BBs drop in just as easily.

Every achievement in the development of blowback action air pistols, up to this point, has centered around .177 caliber BB models with very few exceptions, most notably the Umarex Beretta PX4 Storm, introduced in 2007, and the first to offer a dual 8-shot pellet and BB stick magazine. Sig Sauer introduced its first ASP model, the P226, in 2016 with a similar 8+8 rotary stick magazine. It was intended to be both a sport shooting 4.5mm pellet pistol and a training aid for those using the P226 or P228. It has not been in production long enough to determine the P226 ASP’s success for training, but given that Sig Sauer has followed up only one year later with the P320 ASP, there has been some universal acceptance of the ASP models based solely on their merit as CO2 powered, semi-auto pellet pistols.

By comparison with last year’s Sig Sauer P226 ASP, the hammer-fired model has more features than the P320 ASP, but is an entirely different pistol design with a metal frame and slide, hammer-fired action, and safety-de-cocker.
The new P320 ASP is a polymer frame pistol with metal slide, duplicating a striker-fired design. The DAO trigger pull on the ASP is excellent, however, if you short stroke the trigger it will pass over that round in the magazine and move to the next when you pull the trigger again. It requires a full release to reset, but is overall a very smooth trigger to operate for a DAO and one of the Sig’s best features.

What the P320 ASP has brought to the table is a pistol that actually has “fewer” features than the P226 ASP which, being a hammer-fired pistol, includes a correctly-designed safety and manual de-cocking lever, a functioning slide release (although the slide does not lock back on an empty magazine), and all-metal construction to duplicate the models carried by U.S. Navy SEALS. The centerfire P320 is a polymer framed pistol as is the CO2 model and raises the bar for capacity with its new 30-round rotary belt-fed magazine. Most of the P320’s internal mechanisms, however, are based on the P226 ASP with improvements to accommodate the new magazine design. The loading of CO2 is still accomplished by inserting the 12 gr. capsule into the backstrap channel, only the ASP uses a one-piece removable backstrap and magazine floor plate (revealing an integral seating screw), whereas the P226 ASP offers a hinged backstrap panel that upon closing automatically seats and pierces the CO2. In this respect the P320 is a step back, as it takes longer to load a CO2 capsule.

Again by comparison, the Sig Sauer P226 ASP has a more advanced CO2 loading system with a hinged backstrap that drops open to load the CO2 and then automatically seats and pierces the capsule when closed. The P226 ASP’s magazine design is used by several different pellet-firing semi-autos with an 8-shot rotary-style magazine on either end.
The P320 ASP magazine design is a big step forward with a 30-round capacity on a continuous feed belt. Loading the CO2 is a step back from the P226 ASP by resorting to a one-piece removable backstrap and magazine base. The CO2 is manually pierced by an integral seating screw with a folding handle.

While it appears the P320 ASP is less of a pistol than the P226 ASP, one has to consider the major advances Sig Sauer made in firearms design between the traditional hammer-fired P226 and P320 striker-fired centerfire models, and this relates to how the CO2 pistols differ as well. The P320, as previously noted, is a polymer framed modular design for simplicity of operation and quick interchangeability of components allowing the pistol to be reconfigured for different mission requirements. That simplicity translates to the P320 ASP as having fewer features than the P226 ASP for the same reasons. Unfortunately the ASP is not a modular design, just a basic physical match to the full-sized P320 centerfire model. 

Training & shooting

Having tested the 9mm P320 I am familiar with its operation, which is truly simple, almost the semi-auto equivalent of a DAO revolver since there is no manual safety (the safety on the ASP is a mandatory feature for air pistols) no hammer, and only the ambidextrous slide releases and a disassembly lever. The P320 is built to be as straightforward as possible for a semi-auto, and yes you can say the same for a Glock and several other modern polymer-framed semiautomatic pistols. The P320 ASP shares in that simplicity, perhaps too much so for some, but serves its purpose as a training gun by fitting the same holsters, using the same rail-mounted accessories, having a slide that can be racked to chamber the first round, offering a correct DAO trigger design, weight and balance. You can practice most basic training drills with the CO2 model, even a tactical reload with a spare rotary magazine (albeit the wrong size). As for the airgun’s fixed sights, many military and law enforcement semi-autos have fixed sights, one learns how to correct. The U.S. military did it with 1911s for 74 years.

In the training drills with the P320 ASP the gun was carried in a Galco Quick Slide belt holster. This is an excellent design for concealed carry of a full-size handgun. It is worn here in the 4 o’clock position.
One of several practice skills that can be honed with the P320 ASP is racking the slide. Many consider carrying the gun without a round chambered for extra safety, and thus it is necessary to learn how to rack the slide on the draw. This is also important to practice for clearing the gun and for reloading. One should be aware that the P320 ASP slide has a much lighter resistance than the centerfire models.

During the P320 ASP training session I practiced drawing and re-holstering from a Galco Quick Slide belt rig, racking the slide, sighting, firing, reacquiring the sights, and even a reload with a spare magazine (from another P320 ASP since spare mags are not yet available). I also practiced trigger control with the DAO action, just as I had done with the 9mm model, and like the centerfire pistol, the P320 ASP trigger is remarkably light for a double action only. So, I was able to do a decent basic training session with the CO2 model, including live fire at 10 meters, and aside from the obvious lack of recoil, a slide that doesn’t lock back on an empty magazine (and thus no slide release to practice with), the P320 ASP was a decent understudy for the 9mm. Would I like to see a couple of those missing features? Absolutely, if nothing other than a slide that locks back and a left side slide release. The requisite manual safety could be moved to the opposite side and replace the ambidextrous slide release on the right. As for the advantages of a semi-auto CO2 pellet-firing pistol with a 30-round magazine, it means more time on the range between reloads, and it is hard to find fault with that.

The white dot sights are very easy to get on target and with the smooth, DAO trigger and light recoil from the slide the ASP stays on target.

For the shooting test I went Sig Sauer all the way using Sig’s own branded 12 gr. CO2 capsules, and Sig Sauer Match Ballistic alloy pellets. The Sig cast alloy pellets only weigh 5.2 gr. as opposed to lead 4.5mm wadcutter pellets, which average 7.0 to 7.4 gr.

The Sig Sauer alloy pellets clocked 388 fps as tested by a ProChrono chronograph equipped with an infrared Competition Electronics indoor lighting system. Switching to Meisterkugeln 7.0 gr. lead wadcutters, the rounds cleared the ProChrono traps at 324 fps. The P320 ASP is factory rated at up to 430 fps but the highest velocity achieved was 392 fps with the Sig Sauer alloy pellets.

The target was an IPSC cardboard competition silhouette set out at 10 meters. All shots were fired offhand in 10-round groups using a Weaver stance and two-handed hold (as shown). The P320 ASP delivered a best 20 rounds at a full spread of 2.01 inches, a best 10-round group at 1.25 inches, and best 5-shot group measuring 0.75 inches on top of the “A” of the A-Zone. At 10 meters fired off hand, I am not disappointed with this result from a blowback action pellet pistol, although I have shot tighter groups with a 4.5mm rifled barrel Colt Peacemaker. But that’s really not a fair comparison with a 7-1/2 inch Colt SAA vs. a shorter barreled semi-auto, and I am a revolver guy to begin with, so I almost always have better results with wheelguns than semi-autos.

I was anticipating somewhat tighter groups with the P320 ASP at 10 meters (33 feet) but this is a total of 20 Sig Sauer alloy pellet rounds going downrange at an average of 388 fps and grouping in the A-Zone of an IPSC silhouette target with a best 5-shots clustered on top of the “A” at 0.75 inches, and a 10-round spread of 1.25 inches.

Switching to .177 caliber steel BBS, the gun delivered a best 10 rounds at 1.25 inches. Velocity with steel BBs averaged 332 fps. The P320 ASP was able to fire just over 50 rounds before CO2 performance began to drop off. Peak performance was between 30 and 45 rounds.

Final Thoughts

As a training gun for the full-size Sig Sauer P320 Nitron, the P320 ASP does a fine job of allowing a number of muscle memory disciplines to be practiced and at a very reasonable cost. It is a good understudy for that specific pistol, but is it the best pellet-firing semi-auto available? Since the Sig Sauer P320 and P226 ASP models are currently in a class almost all their own (as pellet-firing blowback action semi-autos), it depends upon what you want to accomplish. Looking at the final results, it is clear that there are a number of CO2 powered blowback action BB models that exceed the P320 ASP’s features, but cannot surpass its accuracy at 10 meters with 4.5mm pellets. If you like the concept of the Army’s new Sig Sauer P320 centerfire model, then you have to like the P320 ASP. And while it may not be all that it can be, it is a pretty good airgun.

A Word About Safety

Blowback action models like the Sig Sauer P320 ASP provide the look, feel and operation of their cartridge-firing counterparts. All arguns, in general, look like guns, but those based on real cartridge-firing models even more so. It is important to remember that the vast majority of people can’t tell an airgun from a cartridge gun. 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.


14 thoughts on “P320 ASP Part 3”

  1. If you are issued a 320 this would be a pistol to have . Since I am not , would probably pass . Ok pistol but for a pellet pistol weak on velocity . You will probably need to insert a new co2 after a little over 1 30 round mag and that won’t be quick . The most interesting thing is the mag which loads easier than their rifle mags . Would be useful in something using dual 12 gm cartridges or a 88/90 gm cartridge.

    • I was able to get about 45 to 50 rounds before the CO2 began to show a significant drop. I don’t think you can get two total reloads out of one CO2. The magazine is very easy to load and yes that is a big plus for the P320.

  2. I think you’ve made it clear that you like the CO2 loading mechanism of the P226 better than the seating screw of the P320. My question is, which one actually seals the CO2 better to prevent leaks?

    The following is an actual customer comment about the P226.

    “OK, I’ve had the gun for a minute now and I’ve noticed one small problem. The first few shots on a fresh co2 cart. seem fine but each shot there after feels as though it has less and less power behind it. Even if I wait 10 – 15 seconds between shots it still feels like I’m running out of co2 even though I know that’s impossible. I don’t have a chrony but I’d be utterly staggered to find the fps on those shots much above 300 – IF THAT!!”

    I’m not sure if their loss of power is due to CO2 cooling effects from rapid fire or due to leaking CO2 at the seal. That’s why I’m asking not which CO2 loading mechanism you like best, but which one do you think produces a better leak-free seal, the cam mechanism or the seating screw?

    Are the P226 and P320 less accepting of other brands of CO2 cartridges? For instance, would say Crosman or Umarex CO2 be more prone to leak in these guns than the Sig Sauer CO2?

    I don’t think you reported your total shot count per CO2 cartridge for the P320. What is your total shot count in the P320 on a single CO2?

    I don’t think you reported how much the point of impact deviated from point of aim. Was the point of impact high, low, right, or left, of point of aim? Approximately by how much?

    • The Sig models are performance tested designs. I have experienced no problems with either CO2 loading system, but the P226 is much faster. Of course, bear in mind I do not do “long term tests” so that is something that comes more from reader feedback. From an intial performance test, I have not had any issues with CO2 in any of the Sig Sauer ASP models, P226, P250 or P320.

      The guns work on all three CO2 12 gr. capsules mentioned as I have used all of them at various times testing the Sig models (except the P320) and have found no difference. I always add a drop of Pellgun oil to the tip of the CO2 before inserting it.

      I was holding under by about 1 inch to hit POA at 10 meters with a full CO2. I have a tendency to pull slightly left with DAO triggers so I corrected by about 1 inch right. But that’s me, not the gun. As mentioned earlier I averaged about 45 to 50 shots before there was any appreciable drop off in CO2 performance. You can pick it up pretty quickly in the sound of the pellets hitting the target, and the feel of the recoil.

  3. I also have a question about the P320 magazine.

    The magazine belt construction, which is it more similar to? The construction of the 8 shot rotary disk for the P226? Or the thicker walled construction of the MCX/MPX belt?

    The following is an actual customer comment about the P226 magazine.

    ” Clip (part that holds pellets and BB’s) did not last long and the plastic wore through after only 100 or so pellets. so Mow I can only shoot BB’s because the clip has an integrated magnet. The pellets which are friction fit now simply fall out of the revolver. The revolver part of this should be made from aluminum, wear from shooting cuts through the plastic pretty fast.”

    Do you think the P320 belt loops are fragile enough to crack after just a few uses? Or are the P320 belt loops the more durable kind like the MCX / MPX belt?

    • Again there are no long term test results so it is hard to answer that question. The loops and link design on the P320 rotary magazine are very similar in construction to the MPX and MCX magazines; pretty durable design. The plastic 8-round rotary magazines probably are more subject to wear. I also prefer cast alloy over plastic. Spare mags are a must.

      • Thanks for answering my questions in both posts.

        When I first heard that Sig Sauer was coming out with the P226 pellet pistol, I thought I would certainly buy it. Then I started to see the negative comments by people who did buy it, and I’ve been hesitant to buy it ever since. I was also waiting to see if Sig would release a version 2 of the P226 pellet pistol that improved upon the initial design. I’m thinking now I may just go ahead and buy it.

        Pyramyd Air still does not have a pre-order listing for the P320, but Airgun Depot does with an estimated in stock date of May 12, 2017 for the black model. Have you seen any announcements about the release date for extra P320 magazines?

        • Actually it is listed and there is a pre-order list. If you click on any photo in Airgun Experience that shows the gun being reviewed, with very few exceptions clicking on the photo will automatically link you to the webpage for that product on Pyramyd Air’s website. You can then review the product specs, order, or pre-order for a new product, and by simply closing out of that page return to the article.

          • Thanks Dennis and Val for the replies. The Pyramyd Air listings P320 must have appeared just minutes after I posted my comments because they were not there before I posted my comment. Trust me, I checked. Before I clicked the Post Comment, there were only four (4) listings for Sig Sauer pellet pistols: 2 P226 and 2 P250.

  4. This review made me drag out aCZ P 09. Very similar except for mag , and it’s less desirable features like a good ball ft sdided safety that can’t be easily disengaged . It also has the twist to pierce co2 cartridge mechanism. It also starts at around 350 fps and drops afteraround 50 rounds to about75 fps less. It also lists velocity at around 400 fps but with 5 gr pellets . I mean come on most shooters use 7- 7.4 gr pellets as a minimum. You made me a believer in the Meisterkugeln 7 grainer. That being said the cz is a pretty accurate pistol . Its shortcoming is the rotary mag which doesn’t seat pellets snugly.The next advance would be a straight line feed like a 1911 mag for 177 pellets.

    • Yes, the 8-shot dual rotary magazines like those used in the CZ P09 and Beretta PX4 Storm can have issues with pellet seating. I have several magazines and switch off so as not to use the same one over and over. The Sig is a serious step forward in magazine design but as you will see in tomorrow’s Airgun Experience not as original an idea as it seems!

  5. Would think this new belt feed technology could be adapted to a drum , opening up some interesting possibilities, like a Thompson , Lewis , as well as others. Or if say a 3″ rounder in a stick type msg , M2 Carbine , Grease gun ,SW43/44 and others

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