Sig Sauer P226 MK-25 CO2 .177 Cal Pellet Pistol

It is easy to load and worked flawlessly right out of the box. I really like the way the CO2 cartridges load and activate. No tools needed. It seems pretty accurate out to the expected 30ft or so. It has a good feel about it and an excellent trigger. I’m mainly using it for target practice when I can’t get to the range for my firearms. It’s really inexpensive fun.

Hoo boy, this is a fun gun.

As I mentioned in another review, my caveat is that I don’t own firearms, but have used many. I have not owned a SIG but have handled the real 9mm version, and it’s completely spot on.
If you’ve been keeping score, this isn’t a licensed replica from an airsoft company (like the KWC P226 X-Five, not to be confused with the X-Five ASP), but an actual SIG Sauer gun designed by them in the US and produced in Japan, sold, warranted and serviced by SIG. They’ve been ramping up their homegrown airgun line under the Advanced Sport Pellet brand–as they put it, “it shoots like a SIG because it is a SIG.” This particular model is based on the 226 issued to the US Navy SEALS, hence the anchor on the barrel.

Fit, finish and appearance:
A friend of mine has a 226, and there’s very little difference at first glance. First, owing to the nature of an airgun, there’s a few omitted functions. The slide lock is non-functional and the ejection port is molded in. Other airguns, like my KWC 1911, feature these and field-stripping capability, but SIG decided these are superfluous to the operation, though included them for visual accuracy. It’s a ding for accuracy to the prototype, and makes for a bit of a pain checking if a round is chambered, but does not detract from operation. The exterior is painted rather than blued with a flat (not matte) black, and markings/logos/warnings are molded in rather than etched or screen printed. The finish is paint, but looks very close to SIG’s Nitron finish—just don’t scratch it.

Where it lacks in these small details is makes up in just how tight the construction is. The gun is full-metal with blowback and a good kick. Report is LOUD and there’s a flash of CO2 vapor from the muzzle when fired. The slide doesn’t return as far back as the aforementioned 1911, but has enough recoil that you feel it. Remember, this is intended as a high-end training pistol. The barrel has a threaded extension and cap for a mock-silencer, which Pyramyd sells but Amazon and SIG don’t as a kit. Still, it adds some realism.
The weight is heavy, within ounces of the 9mm prototype, even with the plastic mags. Slide and barrel, at least on my model, are very tight; I know earlier pieces when this first came out had quite a bit of slop. The grips are plastic with a big “P226” banner on them and should be replaceable with aftermarket versions.

Accuracy and Velocity:
It’s worth mentioning that this is a pellet pistol, which opens you up to a lot more ammo options than a run of the mill BB gun. The mags do accept BBs, have a marking indicating so, and a retaining magnet for loading them, but it’s highly discouraged with the rifled barrel. You’ll lose a lot of accuracy and tear up the barrel, so suck it up and buy some lead or alloy pellets to try out. The original stated velocity was 500+ FPS, but after independent testing they brought it down to around 450, but that’s still only with the lightest aluminum pellets. It seems to like ones in the 5-6gr range.
At 15′, it’s dead-on. Further than that, there’s some drop of POI, depending on pellet weight. Sadly, the sights, though drilled with white dots, are plastic and don’t readily appear to be replaceable or adjustable; you’ll have to go for the X-Five ASP for that. They’re otherwise serviceable for quick sighting if you aim up a bit at longer distances. Windage is pretty much spot-on. There’s an under barrel accessory rail and I mounted the IMI Defense bridge mount (a SIG copy, down to the logo) and red-dot sight and getting good results. It’s far from a competition pistol, but far, far more than just a replica firearm that goes bang. Shoot slow and it will reward you at the target range, or, shoot as fast as your finger can go and blast those soda cans away.

At 10m I’ve gotten best results with H&N Field Target Green and and Crosman Destoyers so far. It does load Gamo Raptors and Prometheus pellets.

Operation and handling:
The magazines are plastic 2×8 GAMO copies and leave something to be desired, considering the heft and finish of the weapon itself. Still, they work, and while they aren’t as innovative as SIG’s newer belt mags, 16rds total is nothing to scoff at. They’ll load BBs, as mentioned, and any standard pellet short of sabot and weird composite hunting rounds (which this really isn’t made for anyway).
There’s a lot of reviews out there lamenting the mags’ propensity to spring out and not stay seated. I thought I was lucky with mine having a nice firm grip on them, but after about 300 rounds, it happened. The problem appeared to be with the release button not returning fully, and a few drops of Pellgunoil solved it for now. Try that before returning your piece.
The CO2 loading is a real innovation here. Stick the cartridge in and slap the backstrap together and you’re ready to shoot. It takes a good amount of force and swiftness to close, or else you’ll lose a lot of gas. Getting them out is a bit of a challenge and I’ve resorted to holding the gun upside down and tapping the front strap, to the concern of my neighbors at the range.
The left-side safety also functions as a decocker, which is a nice safety feature common to the prototype. My local small-bore range doesn’t require chamber flags or the like for air pistols, but with propellant in the grip and no way to check the chamber state, it’s nice to know accidental discharge is highly unlikely.
The trigger action is peculiar and takes a little getting used to. It’s nominally DA/SA, but has a long throw and audible (but not tactile) click halfway through—that’s the magazine advancing. Pull through this or you’ll advance the mag without firing. Conversely, in rapid-firing, you must release the trigger fully, past the reset point. Otherwise, the pull is smooth and fairly light. You wouldn’t be able to tell dry firing, where it’s much jerkier.

In conclusion, this is an excellent machine, and probably the best you can get before heading into the $400 range, which is mostly populated with 10m target shooters. As something made by an actual firearms manufacturer, it’s the pinnacle of realism for both firearms training and all-round shooting fun. Compared to other repeating pistols in the ~$100 range, this is the best of the best, and I’m excited for what SIG comes out with in the future. If your tastes lean toward target and range shooting, definitely look into the X-Five ASP, which is the same gun with adjustable sights, modified trigger, and improved mag, but this one’s just as accurate and powerful. Shortly after I bought this, the X-Five was stocked again and I had a pang of regret—that quickly dissipated after shooting it.

I read that they jam. Sure enough, mine jammed with a pellet in the barrel. They do not back up their item. With it jammed and not working, you are stuck with it and cannot return it. Be warned and buy at your own risk.

Great product. Heavy, feels like the real thing. Easy to use, and powerful.