Well if winter gaming is a must but you still want a quality sidearm...
AEG - MP5K, has a ver.3 mechbox so pretty sturdy shouldn't break stock even in cold weather, and you can just get a rocking stick battery from www.cheapbatterypacks.com
. An elite cell bad boy should give plenty of power, and in winter more is better... lol
For a GBB, I would say something with a LARGE gas capacity, so the cool down is not as dramatic, say a TM highcapa 5.1, has massive
gas capacity but the king would still be the TM Mk.23 Socom NBB. Not a GBB but gas capacity would be more than enough and would keep trucking long after most GBB would stop. Also both are accurate and pretty damn reliable. The socom is deadly quiet too.
Damn now I miss my socom...