I use my Hill MK4 to top off my Wolverine B .22 all the time. I don't have a compressor, so I like to use the pump when I'm around the house to save my buddy bottle for when I actually need it (i.e. at the range, or shooting a lot of pellets in one sitting). I don't find it all that difficult or time consuming to fill my rifle to 230 bar from 190/180 bar. The Hill MK4 is the only pump I've used, so maybe I'm spoiled compared to other pumps. I bought it for the "last resort" filling senerio, but I find myself using it all the time.