The big problem would be finding Dave to sell us the threaded barrel adaptor to attach a straight grease zertThe grease isn't for lubrication. It's a fairly safe way to put a lot of pressure in the barrel. You could do the same thing with water or any other incompressible liquid. It's just easy to do with a grease gun since the fittings are wildly available, a lot of people have grease guns on hand, and grease guns are designed to pump with a good amount of pressure.
to. Where are you Dave???