Entonces así era…

Atorado con esos molestos TANK’s en Left 4 Dead 2 en dificultad experto no llores más, no te pasaremos el nivel claramente pero el usuario URIK a hecho esta informativa tabla para que veas que tanto duran esos bastardos con esas armas, si ya se que te estarás preguntando ¿donde demonios están todas las demás y cuales son las mejores pues después del salto:

Following is Damage Against EXPERT Difficulty Tanks
(at extremely short range, against blind, still Tanks)

Pistols
45 seconds – fast dual pistols – 8 clips (slightly less than 8 clips)
63 seconds – dual pistols manually fired – 8 clips (slightly less than 8 clips) (one trial only)
63 seconds – magnum pistol – 13+ clips (1-2 shells into 14th clip) (one trial)
lotsa seconds – single pistol – 16 clips

Ranged* clips required:
dual pistols 8/blah
magnum
pistol

SMGs
35 seconds – silenced smg – 7 clips (slightly less than 7 clips)
45 seconds – smg – 9 clips (about 8.5 clips)

Assault Rifles
26 seconds – ak47 – 4th clip (more than half way into 4th clip)
31 seconds – assault rifle – 5 clips (slightly less than 5 clips)
33 seconds – triple-shot assault rifle – 3+ clips (second burst from 4th clip)

Sniper Rifles
31 seconds – military sniper rifle – 3 clips (59 rounds)
42 seconds – hunting rifle – 6 clips (59 rounds – same with head-shots)

Shotguns
25 seconds – combat shotgun – 4+ reloads (41=40 & 1 shell)
27 seconds – auto shotgun – 4+ reloads (41=40 & 1 shell)
46 seconds – pump shotgun – 4+ reloads (34=32 & 2 shells)
48 seconds – chrome shotgun – 4+ reloads (35=32 & 3shells)

Melee Weapons

10 swings – Machete (10 swings in 7 seconds)
10 swings – Frying Pan (8.5 seconds)
10 swings – Electric Guitar (8.5 seconds)
10 swings – Police Baton (6+ seconds)

[vía atomix steamforums]