I'm not quite sure that's true. Usually under 70mg, you can fell other opiods, especially strong ones, and especially via IV. I've blasted through 60mg of methadone with dope, morphine IR, oxycodone, and hydromorphone. I don't insuffulate generally, but I know others who do, heroin in particular, and they still catch a nod. Opana, oxymorphone if I remember correctly, is quite strong, although I haven't had the pleasure of ever stumbling upon some, I would imagine you could get still use it. Personally, I would IV it though; however, that's a matter of choice.