Why not use a lower gauge to draw from like an 18 or 16? You can use this everytime, and beacuse they are about as big as a harpoon, the pressure is very high and you don't have to wait the same amount of time it takes to read "War And Peace", just to get 1 ml out. PLUS, when you finish loading, you switch and use another, new needle (the 21 or 22 gauge injecting needle), it is fresh....meaning everytime you stick the needle into the rubber stopper, you dull it. Most guys never used a truley fresh needle, because it was dulled by the stopper before it even got to their ass. PLUS, you eliminate any contamination issues that eventually can happen the "other" way.