I'm interested in this subject, but please excuse my lack of knowledge of these things! I too find sub cut. injections more difficult that IM, but how do these vac guns make them easier? Do you still have to make a 'tent' of skin then inject into that? I've only got 4 sheep and generally only inject them all when I'm 'heptavacing' them, but need to give sub cut injections now and again if using Metacam. Can these guns just be used for one dose? Thanks