My upcoming Only War campaign is going to feature a mixed vanguard regiment featuring a chimera and a Sentinel walker per squad, mixed with some mounted folks for our sergeant.

Now, I have a few questions concerning the weapons and rules when it comes to it when related to vehicles.

First of all, Plasma weapons. Do plasma weapons still inflict the overheat rule should the shooter roll 91 or above? If it does, which facing will be affected by the damage?

Next, reloading. Most weapons seem to have a limited clip, albeit twice that of a normal handheld version. In this case, must the pilot or a helper exit the vehicle and externally load it? Or is it something that can be done internally. Though this does raise the question of how the battle cannon's reloading mechanism works. It has a 12 shell clip, is it an autoloader?

For Plasma weapons, the facing/armor rating that the plasma weapon is mounted on would get hit with the effects. So probably the turret or side sponson.

Internal loading mechanisms for most energy/projectile weapons. Things like missile launchers are usually external, though.

A Battle Cannon, as it has a listed magazine is an automated loader or carousel; though it's almost certainly not a recoil operated mechanism.