I was looking at the errata from TechManual, and see that Protomechs can now (in theory) mount a Gauss Rifle. However, a Gauss Rifle weighs 12,000 kg, so what kind of machine could actually mount this beast?
Here is the closest I can come up with:
Gausszilla Junior
Mass: 15 tons
Chassis: ProtoMech Quad
Power Plant: 15 Fusion
Cruising Speed: 21.0 kph
Maximum Speed: 32.0 kph
Jump Jets: None
Jump Capacity: None
Armor: None(!)
Armament:
1 Gauss Rifle
Equipment Mass (kg)
Internals: Adv. Composite 1500
Engine: 15 Fusion 375
Walk MP: 2
Run MP: 3
Jump MP: 0
Gyro: n/a 0
Control Sys: Clan Heavy 750
Armor Factor: 0 pts Standard 0
Internal Armor
Structure Value
Head 4 0
Torso 15 0
Main Gun 2 0
Legs 16 0
Equipment Location Mass (kg)
Gauss Rifle MG 12000
Ammo (3) T 375
The Quad chassis allows it to get away with the lightest engine possible, although it is slow. Between the Gauss Rifle, which takes up 80% of the weight, the internal structure, cockpit and engine, only 375 kg is left over for ammo (or in theory, armour, but as is it only has 3 shots). By my calculations, this beast has a BV of 325. It also would, presumably, die if anyone sneezes at it.
Similar, but less ridiculous builds, could be put together for the various 10 tonne weapons available (Ultra AC/10, LB 10-X AC, HAG20) and the ERPPC (with HS, 9.75 tonnes). An extra 2,000 kg goes a long way towards armouring these massive weapons-with-legs up!
Thoughts welcome, and mistakes are very possible, I'm new to the game.