Ooh, here's an idea: Laser AC Ammo
Based on ancient Chemical Laser technology (and perhaps the modern Clan incarnation of the same tech), Laser Ammo replaces standard Autocannon cartridges with chemical laser cells, using the Autocannon's standard firing mechanism to trigger the chemical reaction. Each laser cell by itself produces a weak laser pulse, but since ACs fire in bursts of multiple shots each, all those weak pulses add up. This produces alot of heat of course, but most of the heat is contained in the cell which is ejected after use and the laser itself is thinner than the barrel of the AC, so the firing unit's heat sinks doesn't actually have to deal with much excess heat.
Since the AC's barrel is mostly dead weight, a specialized "Laser Autocannon" can be made by taking a standard Autocannon and sawing off most of the barrel. "Laser Autocannons" are half the tonnage as a standard Autocannon, but are unable to use other Autocannon ammo types.
Laser Ammo Rules:
- Can be used in standard ACs and Laser ACs.
- Increases AC damage by 50% round up.
- Doubles AC heat per "shot".
- Is lighter than standard ammo, increasing ammo count per ton by 50% round down.
- Does not explode if critically hit.
- Costs 10 times the C-Bills than standard Ammo.
- Gets its damage halved by Reflective Armor like any other laser.
Hmm... does this concept need a further nerf? Say jamming because the laser cell welded itself into the firing chamber before it could be ejected due to excess heat?