The BEST protection for maintaining your firearms...

Regardless if you have a pistol, rifle, new, old, blue, stainless, silver, gold, or what type of wood. Microcrystalline wax is absolutely the best solution for ANY part you can get it applied to!
This is pretty much what ALL the museums use anymore and it can be safely applied to any type of surface. It's none abrasive and will provide an insulating barrier from even the worst environments. The protection is radically better and you don't have to oil and whip you firearm every time you touch it. Coat whatever you can and oil the inside where you can't This is typically sold under the name brand of Renaissance wax can be obtained from museum supply houses but you can EASILY find it googling on-line or almost any good woodworking shop.
I have, well dozens, of modern firearms too I used this on but the majority of my collection is antique. I can put this on show, handle, and drop them back into the safes and never have a concern. I can only go back 20 years or so with experience but never had a regret!

Tried to find data on heat. What happens when you shoot a shotgun repeatedly as it heats up, does this not effect the wax?

Yes, concerns me too. Usually was would heat and get into crevices and build up. Is that not the case with this stuff ?

I haven't shot a shotgun to extreme temp but I have handguns with no effect I could notice. What it leaves is a very thin layer. I also used this on engraved guns and a build-up in crevices is not a problem. The ONLY time I have seen it leave any bit of a white looking buildup is when someone used it on a WELL RUSTED and pitted firearm which needed some 00 steel wool taken to it first.