My wife bought me a Mosquito for my birthday 3 years ago. They had just been released on the market and she bought it knowing that SigArms makes good stuff. I likewise had problems with it right out of the box, mostly feeding and failure to fire. I tried every kind of ammo I could find, beg, borrow, or steal, but no help there. I sent it back to Sig, but they said they couldn't duplicate my problems and returned it to me. I took it to the range and it performed as it had before. Same problems.
I called the customer service department and got a supervisor on the phone. (At the time I was working at Leupold, and our tech service crew knows folks on their tech service crew and the secret phone number.) I complained loudly and forcefully about the P.O.S. He told me to send it in again, and a week later I got a new replacement pistol. The replacement pistol functions properly, with none of the symptoms of the first one. I finally decided that it likes to digest CCI Mini-Mag ammo and it really likes to be clean. It requires a basic cleaning after about 50 rounds, or so, or it fails to feed. With the right ammo (for my gun) I was then able to figure out which recoil spring works and which front sight I should use. Once all of that was figured out, I find it to be a decent little plinker, but that's all. It is not reliable for hunting, competition, or other serious use. I'm ever hopeful that with more use, it will loosen up a bit. Some day it will probably disappear from my safe, when my wife's not looking, and become trading stock for another, more reliable .22 semi-auto pistol.
I called in to Tom Gresham's Gun Talk radio show one Sunday, and related my Mosquito saga. Tom shared a bit of his sage wisdom, that we should "Beware of LOW serial numbers." Sometimes new model guns need the kinks worked out before they start cranking out good guns.
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