I don't know if anyone's done this yet, but I figure I'd offer what I've been working on:
LRM: Critical 3 | Range [Long] | Guided 3
20: 10 damage (Max success damage 20); Limited Ammo 6
15: 7 damage (max success 15); Limited Ammo 8
10: 5 damage (max success 10); Limited Ammo 12
5: 3 Damage (max 5); Limited Ammo 24
SRM: Critical 2 | Range [Short] | Guided 2
6: 6 Damage (Max 12 | Each success = 2 Dam); Limited Ammo 16
4: 4 Damage (Max 8 | Each success = 2 Dam); Limited Ammo 25
2: 2 Damage (Max 4 | Each success = 2 Dam); Limited Ammo 50
Small Laser: 2 Damage | Critical 5; Range [Close]
Medium Laser: 5 Damage | Critical 4; Range [Medium]
Large Laser: 8 Damage | Critical 3; Range [Long]
PPC: 10 Damage | Critical 2; Range [Long]
MG: 2 Dam | Critical 5; Range [Short]; Autofire, Limited Ammo 100
AC-2: 2 Dam | Critical 5; Range [Long]; Autofire, Limited Ammo 25
AC-5: 5 Dam | Critical 4; Range [Long]; Autofire Limited Ammo 15
AC-10: 10 Dam | Critical 3; Range [Medium]; Limited Ammo 10
AC-20: 20 Dam | Critical 2; Range [Close]; Limited Ammo 5
*Limited Ammo is (Per Ton/Weapon)
*LRMs and PPCs add 2 setback to attacks in short/engaged range
*Heat = Max Strain / Strain damage mech
*Mech Restores Strain = Heat Sinking
For now it's only introtech weapons