I've used a 1 1/2" 20g 5cc syringe to IV morphine, it was a needle designed for IM, but it was all i had at the particular moment. It was very painfull, and tore a large hole in the vein, and bleed immensely. I like syringes with removed needles, and i like 3.5cc terumo syringe, because i inject very large doses of opiates, and need more than 1cc of fluid to prepare what im shooting, be it .8g of tar, or a bunch of oc80s, i need more fluid to sufficiently dissolve such a large amount of drug. Sometimes I use 5cc rigs if necessary, like when shooting methadone oral solution (micron filtered). I have a range of 27-30g of detachable needles. Since i use micron filters frequently since i do shoot pills, i need screw type syringes. I also have 1cc terumos 27g for injecting more potent drugs, like Versed ampules, ketamine and good east coast powder. I am not fixated on injecting. I have shot up countless number of times, but each time i dont particularly enjoy it, or at least not untill i get into the vein and press the plunger down, sending the drug on its way. I've never injected saline out of boredown or that type of thing. When i inject, I do it for a reason, and since i have collasped many large veins, I have to resort to small veins, mainly around my wrists. These spots tend to be more painfull too, and balloon up into a lump if you accidently pierce through the vein completely. Injecting to me is almost a chore, unless i have some good heroin and I know im gonna nod hard.