Hi Renrich,
>Considering the enemy likely to be encountered what was the best armed piston fighter that served in WW2.
Well, here is a comparison of raw firepower (in terms of firepower at the muzzle, international decimal separator):
Me 262: 20,1 MW
Fw 190A-8/R2: 13 MW
Ta 152H: 7,6 MW
Fw 190A-8: 5,5 MW
Me 109K-4: 5,5 MW
Beaufighter Mk 21: 5,3 MW
Tempest: 4,9 MW
Fw 190A-4: 4,3 MW
Typhoon: 4,2 MW
Spitfire IXE: 2,7 MW
Spitfire VC: 2,5 MW
P-47D: 2,3 MW
P-38: 2,2 MW
Me 109G-6: 1,8 MW
Me 109E-4: 1,7 MW
P-51D: 1,7 MW
Me 109G-2: 1,4 MW
P-51C: 1,1 MW
Hurricane IIA: 1,1 MW
Spitfire II: 0,7 MW
Me 109F-2: 0,6 MW
Me 109E-1: 0,3 MW
Rate-of-fire losses through synchronization are not included, but with an electrical system as used by the Luftwaffe should be around 5 % - 10 % depending on type of gun and current flight parameters.
(The MG 151/20 installed have been considered to be using standard ammunition, not the more powerful late-war MX ammunition.)
With regard to wing armament, below a diagram showing the impact of off-centre gun placement and higher dispersion in the P-38 vs. P-47 comparison for their 12.7 mm MGs only (P-38 cannon not considered) for a "zero allowance" shot (placing the aiming dot right on centre of the fighter sized target). As can be seen from the graph, the four guns of the P-38 really give superior hit power for most ranges except the convergence distance of the P-47's eight-gun battery.
My pick for the best-armed piston fighter of WW2 is the Ta 152H as it combines high firepower with centreline weapon placement.
Regards,
Henning (HoHun)