If you find that bullets give a smaller dose than you want them to you can easily widen the hole a bit. Just needs a drill and a clamp and a steady hand. I've modified a couple of the acrylic ones (not that hard but be careful otherwise the plastic shatters and you can NOT get that little part, have to buy a whole new one) The metal snuff rockets are better, harder to drill but also harder to break, just don't drill to far down! To avoid going to far down hold the drill bit against the thing and see how much of the drill can go down (or be more accurate and measure using a needle or something), then out put a blob of Tippex on the drill bit so when the drill is spinning you have a nice white mark showing you how far to go.
Don't worry, we at Camoflage snuff bullets inc. are well aware of the issue and will soon have a bullet with two doses, one which can be abused, misused and invalidate your warrantee for meth and K and one for the cokehead in your life! Our bullet is based on a very simple but utterly brilliant idea, you'll love it...
Harry