AK_MIKE,
Hard to say about how cold will effect it, I suppose if you had a large enough freezer the experiment could be tried, I would certainly hope it would not present a problem.
As far as wear is concerned, I purchased my lower used and it was original set up as a 9mm so it has the appropriate hammer with heavier springs, it is hard to say how many rounds were through this from the prior owner. Currently with my useage and the past useage I cannot discern any wear to the holes. Also the upper to lower fit is very tight but still easy to push out the pins as the material is self lubricating.
Hesse has made some junk I will allow, most of the problems though have been with QC on assembled weapons although I have really not heard much ill associated with his AR's, I rebuilt an FAL-H that would not run (congo model), it was beautifully finished but just had to many hurts done to the front end so I rebarreled it and it was fine, the receiver had a great smooth even finish and was in spec. I have built on 4 other Hesse FAL receivers and all went well except one required 2 or 3 hours of extra tinkering which was very frustrating but for the cost it was worth it.
I really like these kevlar lowers and will probably end up with more down the road, I would also like one of his uppers but would prefer it to have a forward assist and port door, finish match isnt all that important in my opinion where function is more important (spray paint is always an option for the anal).
I will try to get a pic of my carbine tomorrow and post it for you.
Jeff