big battery thats it Iv been playing in winter for 2 years now and never had any problem you can chek my 1st video in winter
note my m4 got full of snow many time never had any problem just make sure to lube it well and id sugest you spay some oil on the metal part to prevent em from rust.
fa-mas m4a1 and thompson all tm stock
P.S. Sorry if the video have many transition that was one of my 1st video.