A friend of mine had this problem. He never went so far as to pop an injector, and I wouldn't either. Turns out he had bought a dented new fuel filter. Grabbed is backup and put it on, bled the engine and all was fine. So in addition to checking the O ring, check the body, too.
Stu Jackson, C34, 1986, M25 engine, Rocna 10 (22#)