Another area where some rule changes have been instituted by Mongoose is combat. In Megatraveller, a character with average characteristics will have a hit value of 3/5. This means 3 pts. of damage will render him incapacitated, while 5 more pts. will kill him. Most of the handheld weapons in Megatraveller do 3 or 4 pts. of damage. These include slugthrowers and lasers of most tech levels. This means a single full damage shot from any of these weapons will knock most characters out of combat. This is where armour comes into play. All weapons have a penetration value and all types of armour have an armour value. In order to achieve a full damage hit, the penetration value must be double the armour value. If it is equal or greater (but not double), it does half damage. In general, armour values tend to lag behind penetration values for a given tech level, so incapacitating shots tend to be rather common. Thus, combat in Megatraveller is best avoided unless the characters have a clear advantage in technology or numbers over their opponents. Another feature of Megatraveller combat is the lack of randomness. The penetration number and the damage of the weapon are fixed. Your weapon either penetrates or it doesn't and you either do full damage or half damage. There are no grazing hits or critical hits. If you have a laser rifle-9 and your enemy is wearing combat armour-12, don't waste your power cell. You will not affect him, no matter how awesome a called shot you make.
In Mongoose Traveller, a character takes damage directly to characteristics, first Endurance, then the other physical characteristics (player's choice). When End and another characteristic are reduced to zero, the character is incapacitated. When all three physical characteristics are reduced to zero, the character is dead. An average character would, therefore, expect to take around 14 pts. of damage before incapacitation and another 7 before death. There is no penetration number for a weapon. You roll a number of damage dice and any excess above what is required to exceed the armour value is applied as damage. This adds a greater degree of uncertainty to each result. For example, the aforementioned laser rifle-9 now does 5d6 pts., while the combat armour-12 has an armour value of 14. It is, therefore, likely that at least a couple pts. of damage will be done to the target and a really good roll could do significant damage. Still, one shot incapacitation against a reasonably armoured character is pretty unlikely. Of course, when PGMPs and FGMPs are being used, characters start getting vapourized pretty quickly.