Sources man sources. Where are you getting your information? Or are you just assuming that is the case. It seems everyone opposed to this "option" for the plane is just tossing out their opinions, and expect everyone else to except it as fact. I am an avid military history buff. I enjoy doing research on things like this and the research I have conducted on this option of the Hellcat tells me that it was not all that uncommon to see these planes flying with 20mm cannons onboard. My research to this point also tells me that the N/P models were shipped from the factory with 20mm's. While I do agree that some of these aircraft probably had them removed and replaced with the .50, it in no way suggests that ALL of them were.
People complain on this board about how unrealistic some request on here are. I don't belive this one is due to the fact that HTC could do this plane very easily, and the number of aircraft produced, shows it was not that rare of an aircraft. This is realy no different than the La-7 with the 2 or 3 gun "option" or the Spit IX with the 4 .303 or 2 .50 "option" or any of the other planes that you can change the weapons mix. The Hellcat -5 models had this option built into them at the factory. I just don't see the aurgument that this was only used in the night fighters and we don't have night as a valid point. If that is the case get rid of the lancaster. The Brits only flew at night with their bombers. We don't have night so why do we need it? Oh but wait, they sometimes flew during the day so we need it.
Do some homework, a little research, have some facts. I keep hearing from you guys that, "They didn't fly them that way, so we don't need it." How do you know? Were you there in 1944? I wasn't so I did my homework to find out. The history books and Tech Specs I've found tells me they did fly them. I'll belive the documentation before I'll belive in opinions and assumptions.