Why are the cannons so weak on the 109-E, yet so strong on the Russian planes?

[TRC Subaru]

I have to defend the Devs a little here; one of the best overall fighters is the Spit IX, turns with the La-7 but with more firepower (at least in the game). I really like the La-7 but I always seem to go back in the Spit because it seems to have more “Killing Power” although I believe the La-7 should be stronger then it appears in the game.

I am not a munitions expert but I did dig up some facts after I perceived the La-7’s canons seem to be firing faster then the Spits (and other fighters). The La-7 has some formidable canons (ShVAK, 700–800 rounds/min), that fire faster then the Spits (Hispano, 600–700 rounds/min). Although the muzzle velocity is a bit slower and the shell a bit smaller I believe more rounds per minute (about 100 rounds/min) would seem to give the advantage to the La-7 when compared to the spit and other planes using slower firing cannons. I believe in this regard - More is Better…or Deadlier

Data pulled off Wikipedia:

Armament - Spitfire
• Guns: Mk I, Mk II, Mk VA
o (VA) 8 × .303in (7.7 mm) Browning machine guns, 350 rpg
o (VB on) 2 × 20 mm (0.787-in) Hispano Mk II cannon, 60 rpg (drum magazine); (VC) 120 rpg (belt loaded, box magazine)
o 4 × 0.303 in (7.7 mm) Browning machine guns, 350 rpg
• Bombs:
o 2 × 250 lb (113 kg) bombs

Armament - LA-7• 2 × 20 mm ShVAK cannons; 200 rpg or 3 × 20 mm Berezin B-20 cannons; 100 rpg
• 200 kg (440 lb) of bombs

Specifications Hispano-Suiza HS.404• Type: single-barrel automatic cannon
• Caliber: 20 mm × 110 (0.79 in)
• Operation: gas operated
• Length without muzzle brake: 2.32 m
• Length with muzzle brake: 2.52 m
• Weight without drum magazine: 43 kg
• Weight (complete): 68.7 kg
• Rate of fire: 600–700 rpm
• Muzzle velocity: 840 to 880 m/s (2,750 to 2,900 ft/s)
• Recoil force: 400 kg with muzzle brake
• Amunition: Ball, Incendiary, HE (High Explosive)
• Projectile weight: 130 g HE and HEI 168 g AP-T
• HE and HEI rounds explosive filler: 6–11 g

Specifications ShVAK cannon
• Caliber: 20 mm
• Cartridge: 20×99R
• Rate of fire: 700–800 rounds/min
• Muzzle velocity: 750–790 m/s (2,460-2,592 ft/s)
• Weight: 88 lb (40 kg) without ammunition for the wing version
• Length: 66.1 in (1679 mm) for the wing version

I’m sure there are others out there that are much more knowledgeable and I would welcome more information on the subject.