I have had mine out for three straight days in the woods, through rain, snow, -20 degree celcius weather, and freezing rain, as well as a heavy hike through the woods.
I left it out in the freezing rain while I was working to put tarps over our cabin at one point to see how it would cope.
After 5 hours, it had 1/4" of freezing rain built up on all the working surfaces. I put a mag in, wacked the charging handle a bunch of times to break the ice off it and charged it, then broke the ice off the safety to swich it to fire, and fired three mags without a single problem.
I do not shoot reloads through this gun often, since it likes to be run HOT, and all my current batch of reloads for my 1911 are a bit on the soft side. If you do not run this gun very hot, you will either have problems with cycling, or problems with locking open on an empty mag. Full power factory or hot loaded handloads are the way to go for the KRISS
This little gun has really impressed me.