Cheap charcoal handwarmer in the pocket soon sorts that problem. Just shot a winter league with .177 field target rifles between -9 and 0 and with the handwarmer in the pocket no real problems loading my pro-target (which is direct to barrel and can be fiddly.
AirArms RN10/EV2 Stock-2007 Big nikko FT Kit
AirArms NJR100 Hawke Airmax SR6 HFT/SFT Kit
Feinwerkbau 600 10 metre
HW77K-zeiler 6-24x44 Work in progress
Webley Vulcan .22 Lovely old relic