This relates to http://feedback.arma3.com/view.php?id=19993, but since the situation significantly deteriorated I decided to report a new bug.

High-calibre aircraft guns inflict way too little (in some cases none at all) damage to medium armored vehicles (APCs). See the following table which compares "rounds of consecutive fire to side armor from 50 meters distance until target explodes" (N/A means that the target does not take any damage, except for specific hitpoints, and thus will never explode):

Weapon \ Target || Marid | Gorgon | Marshall | Kamysh | Mora | Panther

Blackfoot 20mm || 85 | N/A | N/A | N/A | N/A | N/A
Buzzard 20mm || 85 | N/A | N/A | N/A | N/A | N/A
Neophron 30mm || N/A | N/A | N/A | N/A | N/A | N/A
Wipeout 30mm || 30 | 50 | 60 | N/A | N/A | N/A
Kajman 30mm || 25 | 90 | 70 | 100 | N/A | N/A

The table lacks MBTs, since none of the guns is able to scratch one of these (except for external hitpoints, again).

It's particularly astounding, that a dedicated tank-killer cannon like the Wipeouts's huge Gatling (see Wikipedia: GAU-8/A Avenger) cannot harm some medium armored vehicles and is even outperformed by the Kajman's comparatively tiny cannon.

This must be a regression from somtime between August (see mentioned bug report) and now, which deserves a fix, since it turned the Wipeout from a good and for pilots challenging tank-hunter into a boring lock-on-fire-missile-and-forget-tool. {F25314}