I don't think we were talking about adding gun pods to P40s or P51s, they already have multiple wing guns.Sometimes prejudice will trump actual testing (and if testing is not done?)
Please note on the P-39 that the ammo for the under wing guns was held in the wing, pretty much where the .30 cal ammo went. Trying add an under wing pod to a P-40 or P-51 is going to be a lot harder or need a much bigger pod.
Russians tried under wing gun pods on the Mig-3 but the change in performance meant that the planes with pods often could not keep formation with the planes without pods. The Mig 3 had one synchronized 12.7mm machine gun (not through the hub) and two 7.62mm machine guns so if any modern (post I-16)
True but the MiG 3 was already being phased out as a front-line fighter (relegated increasingly to PVO and the Far East) by 1942. By 1943 almost the entire Soviet arsenal (of Russian made planes) was armed with 20mm nose cannon (LaGG -3, La 5, Yak 1b, Yak 7, Yak 9). The P-39 of course had either 20mm or 37mm.
as far as ace's comments go, I once had a rifle coach I knew well make this comment about Gary Anderson who used to tilt/cant his rifle to one side when shooting
People in many sports or endeavours will copy the equipment or style of most successful without fully understanding the effects of the equipment or the reason for the style.
Interesting philosophical observation but I think you are probably aware in saying that nose guns aren't more accurate than wing guns you are taking an outlier position. Not only most pilots, but most Air Force staff seemed to recognize this was the case, particularly for widely spread (as opposed to closely grouped) guns. It's not just a matter of the convergence point (and therefore estimating range etc.) but it's just the fact that each gun shoots bullets outward in a cone, and those cones diverge more and more.
I think for an outlier position you should do a little more to support your claim.
I would concede though, certainly in part this also has to do with the culture and training of the pilots. And that is a complex can of worms.
EDIT Also... gyrostabilized gunsight (I think available in 1944?) clearly made a big difference.