I thought some of you might get a kick out of this! It really helps keep the barrel cooler on my 225 viper. I usually chamber it for 2-3 minutes between shots at the range. normal old walmart bait bubbler. drilled the primer pocket out on one of my old cases, and shoved the air hose in all the way to the neck. Just chamber it like a live round, turn it on. I pull it out by the hose and shoot again! This may not work too well on a bigger bore, but it gets fair airflow down a 22 bore. 50 grains of Win 760 down this barrel gets warm in a hurry without it. Got 40's running 4,500 though.