I used to work in a factory that built sleepers for the backs of the large highway rigs, on some of the stations on the assembly line we would shoot a good dozen tubes of sealer a day, we started out with decent quality had guns, broke all of them, then went to good quality hand guns, busted them too, and we finally got the bosses to buy the good quality air guns. With a pressure regulator right on the unit, you could adjust the flow on the fly, and we certainly did, we had to keep a precise amount of sealer flowing, too much, and you spent a lot of time cleaning it up, too little and it would not seal and would fail inspection, big trouble
The better air guns have a release each time you let go of the trigger, if you don't have this, the always seem to leak or drip a bit of sealant after you let go of the trigger, which, at the very least, is messy. We held on to our own personal guns like they were made from gold, no one could borrow it, not a chance, once you got your gun dialed in, you did not want anyone messing with it.
Tell us how you get along with it Carol!