At roolipelit.net forum I asked about weapon damage some time ago and got a suggestion about making damage according to weapon caliber and ammunition type. That sounded cool, so that's what I will do.
I was also linked this website http://world.guns.ru/main-e.htm with lots of weapons and statistics. I just have choose what weapons I want to include. Three shot bursts,clip sizes, weights and all these details are included so I don't have to decide those myself.
When I have a set of weapons I want to include in rules I just have to put ammunition in order from smallest to biggest. Then put damage on those ammos.
I also thought there could be some basic damage with each weapon roughly based on different variables like speed of bullet. This could make small difference. For example shooting Parabellum 9mm or Glock 18 even though they use same ammo. Basically I like this basic damage idea also because when you already have hit you want to deal damage.I dislike games where you score awesome to-hit roll and then deal lame 1 points of damage. So weapons have this basic damage what is dealt and rolling dice is the additional "how badly the bullet actually hit you". Same thing is with melee weapons in many games. Melee weapons have this basic damage - strength bonus of wielder (Sword d8 damage + strength bonus). So why cannot firearms have this basic damage (Bullet d8 damage + weapon bonus)? Also if more detail is needed optional rule could be that weapon in weaker condition its basic damage is reduced.
How to decide how much damage bullets do then? Simply I take initial characters lowest and highest possible health points and the medium of health points. Then I take bullet size from the middle and decide how deadly I want it to be dealing average damage. Then move up and down the list downgrading and upgrading damage values to less deadly and more deadly. I think it's simple pattern to follow.
For example medium bullet (9mm perhaps) needs three shots to kill average character. .22 pistol needs 4-5 shots maybe and powerful sniper can deal damage way over possibly even one shot killing maximum health points character. Remember, this is average damage so lucky character could survive that sniper shot if dice are favorable. Although, really bad-ass sniper could have horrible base damage what is the killer.
Same way with explosives. If explosives basic damage is huge it kills character if it is a hit. The difference comes when explosives are used against armored vehicles or buildings or giant robots or other big targets.
I think that this is a good idea. And simple and follows certain pattern. And if there is certain logic in firearms I think I could write small easy tutorial how weapon damages were determined so different Game Masters could easily write their own weapons in similar pattern.
I think I will use this commonly if I find it good idea in practice and test. I also should shuffle my rpg books through to find out what logic they use in weapon damage and can I find a pattern there.Easiest way would be to take a rpg with lots of guns and choose what I want to use. Then just convert damage system to suit my game. But that would be a bit too easy and not as much fun.
If this post is confused I got new ideas how to write this during the session and also I was distracted several times writing this. I hope it is readable.