My A-Bolt Stalker has hunted in cold nasty weather with ice and snow. It has a synthetic stock but its not stainless. I have not had any problems with the trigger at all. I do not ever put any oil on or even near the trigger
I don't find snow and ice nearly as bad as rain as far as rust on rifles is concerned.Most snow and ice stays on the surface and can be wiped off,whereas rain gets into the internals and you can't dry them out without disassembling the rifle.I agree 100% on never putting oil on a trigger assembly.