These light autocannons are capable of delivering a high number of low caliber rounds in a very short period of time. The individual damage is not high, but if the target can be kept in the stream of bullets, significant damage can be done. Ammo is limited.
*Webmaster's note* Also, if you ignore the fact that you're being shot at with a machine gun, like think "Heck, it's weak," don't do that. I ignored an APC once and it blew off my Bushwacker's left leg.