Yep my grunt sure does freeze up bad. I have a Carlton grunt tube of some type and i am not too happy with it, I am changin it up for this year. It seems the call is fine until you grunt 3 or 4 sessions then the moisture from your breath must condense and freeze it up. I have to keep it down my shirt and then pull it out everytime when i grunt. It makes for more noise, more movement and more of a hassle. I would be interested in hearing of any grunt calls that won't freeze up when its dips below zero.