Just noticed something funny.
Hitting vehicles with the grenade launcher ALWAYS does full damage even at ranges where the nade does not explode.
Of course that's still 10 grenades to the rear of an lightening to kill it BUT at least you can do it from point blank.
It always does the same damage to vehicles, not full.
Explosive damage in PS2 has two components; direct hit and splash/explosive.
Most vehicles are immune to
most splash damage (obvious exceptions are tank mines, C4 and flak). Generally, hitting an enemy tank with any projectile will do damage based purely off the direct hit damage times any modifiers (armour and damage type,
see here). Hitting infantry will do damage based off of the direct hit damage
plus the splash damage. As a rule, AV weapons are direct hit based and AI are splash based.
I can't find the damage values now, but if you hit infantry with a UBG inside its fuse range you will only do the direct hit damage, without the massive splash/explosive damage that makes it a OHK and farming glory tool. Against vehicles you will
always only do this damage, with the bonus of doing some splash to nearby repairing engineers.
Also worth noting that for all explosives (AFAIK) there is no damage falloff on either component. So you always do the same direct hit damage and splash damage with rockets/grenades at any range, often making AV weapons like the Enforcer/Halbard or AV turret preferable as long range AI weapons to the Basilisk or AI turret. Also, all weapons have a direct hit damage, even if it's tiny. See kills with revive grenades (IIRC concussion/flash actually do some minor splash damage to the tune of 1HP so that they give assists).
With regards to the resupply delay, I think there may be a way to bypass it. May count as an exploit. Will have to test when I get home this evening.