Shouldn't be a concern, I've fired lots of synthetic at minus 50 or colder, only one I'm aware of having problems was the early Ram Lines but they were injection molded. When glass stocks first started, a few manufacturers sent me samples to try out and never saw a problem. Bigger problem was trying to avoid double-based powders, ..... they liked pressure excursions at cold temps!!
When you live here and want meat, you quickly learn to deal with Real Cold!!
