I know its not a long term definitive answer but I've dropped a Glock 20 in a silty stream in below freezing temps(I stupidly had it in a chest rig with the keeper strap disconnected and was filling a canteen), spent another 2 days out in the woods after that, and then did a couple of mag dumps before getting in my pickup with no problems. Guns and ammo are pretty reliable these days. It's relatively easy to Mcguyver gun cleaning stuff. You have oil if there' a vehicle and if you have p-cord and cloth you can clean the barrel.