When it's getting colder, you would prefer more consistent performance with a CO2 blowback. Laylax got what you need, a CO2 blowback version of the SIG Sauer ProForce M17 airsoft pistol... "SIG AIR has released a long-awaited model upgrade of the U.S. military-style pistol M17, which complies with Japanese regulations and features a unique inner frame structure, polymer slide, long CO2 magazine, and Picatinny under rail. It is also JASG certified."