You don't say where you are. In the U.S. FAR 91.15 allows the PIC to drop objects from aircraft if the operation doesn't create a hazard to persons or property, etc., etc. Read and heed.
Based on published stories about this activity, you are very likely to get some blowback inside the aircraft, and will almost certainly get some of the remains on the outside of the fuselage. On a light aircraft this would probably only mean a good wash job after landing, but in a helicopter, with that tail rotor back there...???
Personally, I wouldn't advise it.