problems with mounting a GPMG in the cabin of an S-61A
Had chat recently with a former Air Quarter Master of an Sikorsky-61A. He mentioned that during the 1970's when his squadron was supporting troops on operations conducted against the communists and when they were coming under ground fire, it was decided to pintle mount a GPMG in the cabin of the S-61A. The problem was that during flying trials it was found that the whole cabin and cockpit would be covered in gun smoke because of the rotor wash, resulting in the project being abandoned.
My question is if there were 2 sliding doors in the S-61A instead of just one on the starboard side, would this problem have been encountered? Or could it also have been due to the level of propellent in the 7.62mm ammo? Have any other S-61 or Sea King operators ever mounted an MG in main cabin?
The H-34 is known to have had a 12.7mm HMG mounted and if I'm not mistaken, like the S-61 it also only had a sliding door on starboard.
Interestingly, I've read that troops in Rhodesian Aloutte 3s were forbidden to fire their SLRs against ground targets as the rotor wash would result in the spent casings hitting the rotor blades.