accuracy, kill, and warhead size
 

accuracy mean it is more likely to hit the target.

warhead size seems to affect shell. A larger warhead retain more kinetic energy over longer distance and a larger HE is more likely to kill infantry.

but how do HE/AP kill affect the weapon? for example the bren have accuracy 21 and he kill 5 compare to the mg42's accuracy 17 and he kill 10. Does this mean the mg42 is less likely to hit but will likely cost twice as many casualty? HE/AP kill and warhead size seems to overlap in how they affect the weapon.