I've got a grunt tube I've had for years, and it has served me well. I've called in a few small bucks with it that I've shot; however, it tends to stick, especially in colder weather. When it sticks, due to moisture, it sounds like something wheezing with asthma.
Are there any that aren't affected by cold or moisture?
yes my PRIMOS hardwood grunter best grunter ever
If you have a grunt tube that sticks or freezes you can use it backwards instead.
Instead of blowing air through the top turn it around and draw air in the other way. This way no moisture goes across the reed but you still get the same sound.
go to ducks unlimited web page they probably have a fix for that.
I just picked up a Flextone, what a great call for $10.00, I'm very impressed and so were the couple bucks I've called in the past few days!
Turn it around and suck through it. It does sound a bit different but it won't freeze up on you.