Obviously the 8 x .50's of the P47 are preferable to the 6 on most other US fighters, but having the 8 included would totally negate the inclusion of the more standard 6, which no-one would vote for given the opportunity for 8.
The same story applies to 4 x .50's and 2 x 20 mm cannon (also used in only one plane, I think). Much preferable to the 6 x .50's or the 2 x 50's & 2 x 20 mm cannon, but the latter two would not be chosen by anyone (or few) given the choice of the former.
Besides, the rarity of the two choices (8 x 50 OR 4 x 50 & 2 x 20mm) I don't believe constitutes the 'usual' choices open to those that would decide these things from '39 - '45.
So which of the above would you consider your best bet, when taking into account the usual limitations that were placed on the number of rounds that could be carried because of room available for each gun etc.
I know some will say "it depends if you're dog fighting or ground attacking etc" - good point! ;D But they're Fighters, so we'll stick to air combat (against other Fighters or maybe Fighter/bombers).
You can use your rockets and bombs on the ground.........lol


To make it more interesting, a basic rule of thumb, which may not have been considered in these decisions at the time but now plays a major part in the comparisons made with regard to which was more effective overall, is the weight (or amount) of lead thrown each second by each type of gun. It's actually not a very oft studied area of combat aviation, surprisingly.
But then I would always take into account how much 'firing time' I had also. A trade-off, if ever there was one! ;D

Go for it, and we'll see if we agree with the designers and decision makers of the day.
Of course, feel free to justify your choices (or rejections) in anyway you like. IT"S YOUR PLANE, YOUR LIFE AND YOUR DECISION, TODAY AT LEAST....................
