I have a friend who used to slam straight oxy and percocet, and it did not end well.
And you are not even sure these "oblong a333" pills are actually percocet in the first place, so my suggestion would be to back down right now. Don't risk it.
Pills have extra fillers and binding material that holds them together man. Slamming that stuff is no good for your blood stream, and it will end up in your chest and lungs where it can cause serious complications.
Ok I don't know all the medical terms for it, but I have witnessed it with my own two eyes and that stuff is messed up!
If you really want to get that stuff used up, then why not just light up a bowl or something. One hit should be enough to tell you whether it's oxycodone, hydrocodone, percocet or what..