Posted 27 November 2011 - 02:13 PM
So the general consensus is that LRMs are easy and quite acceptable to make difficult or dangerous or ineffective to use at close range, through a combination of delayed arming time (to prevent detonation in the launcher and friendly-fire splash damage if fired too close), missile divergence at launch to prevent missile fratricide (the missiles diverge away from each other immediately after launching so they don't collide), making LRMs spread apart at close range before clustering back together and converging on the target, and arched missile flight paths (the missiles are fired 'up' in an arc to allow for fire over obstacles, etc.). Players would then be able to mix things up with various types of missiles made by different manufacturers.
Default missiles would have a delayed arming time after launch, making them rocket-powered rocks inside that minimum range, and would widely diverge after launch, like a wide-choke shotgun blast. Many mechs would also fire their missiles angled up, because of the location and angle of the pods (though not all mechs - some would fire straight-forward, but iirc all the mechs designed to be dedicated LRM boats have their pods oriented to fire in arcs). Missiles from some manufacturers would hot-load, with the warheads armed and ready to go in the launcher, at the risk of them going off in the pod, and setting off the whole pod of missiles, or getting splash damage if they hit a target right in front of you. Missiles from other manufacturers would have the missiles stay clustered together out of the tubes, at the risk that they would collide with each other. Missiles from other manufacturers would do both, with the additive risks of both (like the risk of your hot-loaded, clustering missiles colliding right out of the tubes and setting off the whole pack right in your face). Personally, I think the arching angle of missiles firing should be mech-dependent, to help give points of difference between different mechs.
As for PPCs, a Particle Projection Cannons basically IS an over-sized laser, it just uses hydrogen ions, or protons, instead of photons (light particles). It's a beam or bolt of charged particles, hence the recoil and kinetic effects despite being an energy weapon, and electrical surge problems. Now, the canonical explanation for PPC range limitation makes some sense - you're basically hitting the target with a stream of charged particles that can play holy hell with a target's systems, and a feedback along the ionized trail to your mech that hits you with the same EMP-like effects is not something that you want to have happen. The problem I have with this is that the effects would be severely limited - it fires a stream of protons, which are charged particles, but they are not going to act like an electrical surge because they're not electrons, which are what conduct electrical energy along wires and which are what cause the first-tier and main damaging effects of a nuclear EMP (check out the wikipedia page on electromagnetic pulse if you want some specifics on the physics behind that). It COULD still potentially work, though, if the PPC induces a high positive charge in the area around where it hits, that is rapidly neutralized by a flow of negative electrons to the area - causing some electrical drain and static discharge effects. Depending on how the PPC actually works, its firing might also create a heavy negative charge in the cannon itself, which would have to be neutralized. Presumably, if this is so, the cannon has mechanisms to safely neutralize the charge while the weapon recycles (possibly part of the need for the recycle time in the first place?), which at close range could cause a feedback surge from the target along the ionized plasma trail of the energy bolt back to the weapon itself, which could, hypothetically speaking, act as if the weapon fired and partially 'bounced back' into itself, which would be what is known as A Bad Thing.
So, in my opinion, and as others have suggested, having a PPC fire at reduced damage inside a certain range (90 meters being the canonical minimum safe range), with an option for players to override the safety protocol, or buy weapons that override the safety protocols, at the risk of causing a feedback into the weapon for, say, half damage or so of the weapon, with the damage bypassing the mech's armor and being directly applied to its internals. This is both canonical, and at least kinda-sorta consistent with real-world physics (though being a physics major myself, I will say that they seem a bit stretched to me, but not unreasonably so), and doesn't introduce silly and hard-to-explain things like a charged particle beam firing in a cone that somehow converges on itself some hundred meters or so beyond the barrel of the weapon, or a weapon that is fairly precise to aim at 900 meters suddenly going all wonky and all-over-the-place inside a tenth of that range...