Sorry John I didn't see this.
I haven't taken any of mine out in sub zero (f)/ -16c temps. I have taken my Chapuis out at freezing and other than a bit of arctic grade auto grease on the hinge. I didn't do anything to the lock assy. Because of the freezing rain/mist/snow I put several heavy coats of Johnsons Paste wax on everything. Then electric tape wrapped over the ends of the tubes. It worked fine that way for a black bear.

We did have another shoot today but the temps were just a few degrees above freezing. Everything worked well. I'm sure that Omni-Bob will toss up some new pictures here.
We had new shooters and 'new iron' also. Stay tuned!