
Standing at the cabinet 'o smaller semiautomatic pistols in the gun shop, I had a number of choices arrayed before me. With a .22 target/plinking pistol in mind, the shop keeper laid on the counter the usual suspects from Ruger, Browning, and S+W. All had their good points and bad, but something whispered to me "Look again....". Another .22 still resided under the glass, and it was one I had missed at first glance. A Sig Sauer Mosquito in two tone, with silvered slide and black frame.
The Mosquito is a double action .22 rimfire semi-auto built by Sig to duplicate the feel of their P226 and P220 model pistols. Brought in at 90% of full size for those models, the Mosquito has controls and functions that match it's big brothers. The only control that does not match is the safety. The Mosquito has a slide mounted thumb safety lever, while it's slightly larger brothers do not.
There is no requirement to use the slide mounted safety, and it can be ignored if desired. The decocking lever safely lowers the hammer, just as it does on most other Sig's.Looking at the specifications, it quickly becomes apparent the Mosquito may be 90% the size of a P226, but it's a 98% duplication of the size and shape of the P229 9mm compact double stack carry pistol. This makes for an interesting possible combination; the P229 for defensive or concealed duty carry, with the Mosquito for low cost and plentiful practice.
The Mosquito seems to have been built with several ideas in mind. One is clearly the adherence to clunky old Sig Sauer solid dependability. Another, a target of meeting the training needs of those who own the bigger centerfire pistols but desire a matching .22 for practice. Lastly, the pistol appears to have been built with the motto "If it can be made of polymer, do so!"

The frame is plastic, as so many pistols are today, but Sig went far beyond that. The sights, hammer, trigger, mag release, magazine, and even the barrel are plastic (the barrel has a steel liner). The pistol has a great deal in common with the plastic box it comes in.
The pistol is mounted with an external safety key, but it's fairly well hidden. Almost unnoticeable, behind the magazine well on the butt is a small hole with a flat blade in it. The pistol comes with a key to turn the blade. One direction activates the pistol, the other deactivates it. The pistol also comes with what appears to be a red plastic empty chamber flag that can be inserted into the chamber. Reading the manual discloses the flag also doubles as a clever 'dry fire' plug to protect the chamber mouth from the firing pin.
The sights appear to fixed, but are actually designed to be adjusted. The rear sight has a set screw, and loosening it allows the simple and rugged slotted sight to be adjusted left or right. The front blade is fixed, but unique in my experience the pistol comes with two additional extra sights. All three are different heights, and once the best ammunition is chosen the proper sight can be installed to match it's point of impact. The sights are 'three dot', with tiny but bright yellow inserts installed in
them.Field stripping for cleaning is amazingly easy. With the magazine removed and the pistol assured as empty, the take down lever is simply rotated 180 degrees. At that point the slide is pulled rearward and lifted up off the frame guides, and then allowed forward. This leaves the frame with barrel attached, the slide, and a recoil spring with a guide. That is all the is required for normal cleaning.
It should be noted the pistol also comes with a spare recoil spring, and the simple field stripping is all that's required to change it. The extra spring is of a different rate, and can be used to tune the pistol to the ammunition chosen. To me, this demonstrates an understanding that .22 rimfire ammunition varies significantly, and erratically. Changing recoil springs on a blowback pistol is the simplest way to tune one, but getting different springs can be problematic. It's nice that Sig thought ahead on this.
Just for fun, there is also a heavy keyed security lock that comes with the Mosquito. It has a padded chain that's long enough to install down the barrel and back into the Master style padlock. What's slightly humorous about the lock is this: it may contain more steel than the pistol itself does.

The magazine is plastic, but fairly well built. It is also the source of the only problem encountered with the pistol during it's first range experience. The very first round ever chambered in the pistol misfed, with the bullet hitting the back of the barrel instead of being guided into the chamber. There was only one more feed failure during the first one hundred rounds fired, and that was the final round in a magazine that launched itself from the ejection port, rather than chamber. It was found in the shooters shirt pocket, still unfired and unmarked.
A nice feature the Mosquito has, and one not assured on all .22 autos, is a magazine slide lock. The slide remains open on an empty magazine, just as it does with it's
larger siblings.For some reason, Sig Sauer regards the magazine as an exceptionally valuable article. The pistol comes with only one, and Sig wants $44 for an extra one. Midway USA has the same magazine in stock for $10 cheaper, but that is still a little pricey. Spares will be purchased, but not too many of them.
Fired for the first time on the range, the results are quite favorable. Where I have run into new Ruger MkIII's that required hundred of rounds of break in to begin functioning decently, the Mosquito began cranking out target after target with very few function issues. Only the two feed problems previously mentioned, and nothing else of exception to note. It may help that Sig Sauer includes with the pistol a $10 coupon on four boxes of CCI Mini-Mag rimfire ammunition. This helps people make the proper choice of breaking in the pistol with quality ammunition, rather than bulk pack cheaper offerings.
Sig includes a card with the pistol noting that it's been tested with CCI Mini-Mags and functions well with them. The same card also specifies a special lube point, and that the pistol needs to be regularly cleaned and lubricated. It always amazes me how many folks will take a new pistol out of the box, never clean it, and complain about function. These things are machines, and need care to operate correctly.Accuracy wise, the Mosquito performed as expected. For a light weight short barreled .22 new out of the box, the pistol grouped decently. The first fifty foot group from the bench was under four inches, and when the trigger was mastered that shrunk to a little over two inches. It's not a 'target' pistol really, but much better suited to defensive practice, and the accuracy is more than adequate for the job.
More to the point, the Sig Mosquito immediately and naturally fell into it's niche of being a low cost training pistol. It fit the CCW belt holster perfectly, and the functionality of the pistol allowed for an excellent practice session. Over 100 rounds were fired in draw/double tap drills in the span of half an hour. With the 9x19mm, this would have meant an ammunition cost of about $40. With the Mosquito, it cost only about $6, and that's with premium rimfire ammunition.
I am becoming enamored with the idea of a rimfire pistol that exactly matches the size and function of my carry pistol. I can foresee a Sig Sauer P229 in my future as a CCW weapon. While my S+W M+P 9c has been a steady companion for several years, it has a few drawbacks the P229 would neatly solve. Add in the idea of low cost practice with the mosquito, and it becomes a winning combination.
Reading owner reviews on the 'Net, the Mosquito generally gets poor marks. Comments about feed failures with various ammunition, a trigger not up to match standards, and the fact that it's made of plastic and pot metal. All that taken into account, if the feed issues can be solved by using proper ammunition, then the other problems are more of expectation than manufacture. The mosquito is not a target pistol, and it's certainly not intended to last through several generations of shooters. It is made of cheaper materials, and this is reflected in the low cost. What it does have going for it is ergonomics. It's built as a low cost trainer for the Sig duty pistols, and for that function it seems to fit the bill. If Sig made one of quality steel and charged a few hundred dollars more, I'd rather have that, but they don't.
There will be a high quality .22 pistol in my future, of that I am sure. I have my eye on a K-22 as I write this..... but for now, this little Sig hits the mark as a training pistol that's cheap to buy, and cheap to feed. Stay tuned as a I wear it in, and attempt to wear it out. More reports are coming......
(Bit of an update....)
Looking at Sig's web site, I have discovered they do indeed have full size and high quality rimfire pistols built to exactly match their carry pistols. They also have rimfire conversion kits to fit most of their carry pistols. This is promising!
As for the Mosquito... I'm going to try and wear it out, while reporting on the progress as I go. We shall sort out the 'I heard' from the reality soon enough. Will it hold up to thousands of rounds on the range? Or.... will it prove to be a FTF waiting to happen? Stay tuned!










