Didn't an Army Cobra pilot go up and demonstrate mast bumping in his AH-1?
Can't remember the specifics, but pretty sure that he went up very high and pushed the stick forward, but only after sensibly donning a parachute. Entered 0g, rotor seperated and then he bailed out, but his CPG might not have been so lucky.
ISTR is was something to do with proving that mast bumpping was at the root of so many UH-1s augering in in Vietnam.