We are in the process of re-writing the rules.
Differentiation of Weaponry
We have added a second stat for weaponry - Penetration (PE). This directly opposes Armour in our updated Shooting rules - in that a high Penetration (PE) with negate enemy Armour (AR), a high Penetration (PE) means you can penetrate armour more effectively - but it doesn't directly translate into more damage - Damage Output (DO) is intended for this purpose and the rules now show this difference.
We did this because we felt that there wouldn't be as many differences between different weapons, apart from Weight (WE), Power Consumption (PC) and Damage Output (DO).
We also think that we can help make each weapon unique by offering weapons with high Penetration, low Damage Output because certain weapons are exceptionally good at penetration but do very little damage internally. Then there are certain other weapons which are poor at penetration but do a lot of damage if they do penetrate and weapons which mix and match the two statistics - allowing players to pick the weapons they think may do well against enemy Mechs - and give them a reason to pack multiple types of weapon on the same Mech. It should also lead to more strategic play - with players picking off the higher penetration weaponry to starve off any one- hit "kills".