[weby]

I think Warthunder assumes that they are firing AP ammo, like the Brittish 2 pounders that were also 40mm fired. The 2 pounder was fairly ok anti armor weapon early on in the war, so a 40mm autocannon would likely be too with AP ammo.

With saphe ammo: Not really useful unless you get flanking shots against lighter tanks or facing something like an armored car or the equivalent(pz1).

Later in the war: not useful against anything called a tank even with AP.