obj/projectile
   var/delay=2//The speed they fire, the lower the quicker
   var/damage//The damage they cause (integer)
      
   proc/shoot()//Call this when you want them to fire
      walk(src,src.dir,delay)

   Bump(mob/M)//Redefine their Bump()
      if(ismob(M))//If they are a mobile
         M.life-=damage//subtract their damage from their life
         del(src)//delete the object

   Bullet/*Bullet and missile are extentions of the type obj/projectile.
           Example: Bullet =  /obj/projectile/bullet*/
      icon='bullet.dmi'
      delay=1 //Set their delay and damage
      damage=5
   Missile
      icon='missile.dmi'
      delay=4
      damage=20

/*Now for the player interaction*/
//Do this if you want the mob to keep it always
mob/verb/Fire_Bullet()
   var/obj/projectile/O
   O=new/obj/projectile/bullet
   O.loc=usr.loc
   O.dir=usr.dir
   O.shoot()//Fire it!

//This is the verb if you want it linked to an object

obj/Missile_Launcher
   verb/Fire()
      set src in usr //If they are carrying it
      var/obj/projectile/O
      O=new/obj/projectile/missile
      O.loc=usr.loc
      O.dir=usr.dir
      O.shoot()//Fire it!

//I hope this helps, and it is easy to change around