Plus trying to hoik the old cartridge out which inevitably gets stuck in there, air locks and often when pulling the plunger out to solve the issue a load of grease gets forced out the top of gun when the plunger comes out. I've always managed to make a mess with the old style cartridges. Just can't see the argument for them aside from saving a few quid on cartridges
My alemite one just pull lever out,unscrew handle, then release handle and cartridge is ejected into bin.
I usually open the ring pull with a pair of pliers. Makes may Less mess. And no air lock issues.
I think the biggest problem is rubbish grease guns.
I also wear a pair of disposable gloves to grease up as regardless of grease gun you end up getting grease on your hands cleaning the muck out of the grease nipples