Shortround6
Major General
MS.406 was not weakly armed, it sported a 20 mm cannon that fired heavy shells at excellent muzzle velocity, on very good RoF; plus two MGs. It was indeed lack of air defence network that was French undoing, along with doctrine and startegy.
I agree with much of what you say except the above. Contrary to much of what has been Written it seems the majority of MS 406 aircraft were armed with the HS 7 or HS 9 cannon and while there was little to chose in the power of the individual cartridge between the HS 7/9 and the HS 404 the HS 7/9 fired at around 360-420 rpm or about 2/3 the rate of fire of the HS 404.
The MAC 34 machine gun seems to have been pretty good (or at least no big complaints) but in the MS 406 it seems to have been fed from a 300 round "drum" or container for the belt while some other French aircraft used a more normal belt arrangement with more ammo per gun.
The MS 406 carried 60 rounds of very powerful ammo to the 109s 110-120 rounds of 20mm ammo, and only 600 rounds of MG ammo to the 109s 2000rounds.
The 109 was probably carrying to much but the MS 406 may have been carrying to little.
The D 520 had four machine guns with 500rpg in addition to the cannon.