Penetration

Sometimes it seems like a given round is underperforming in GURPS.

But it's a game, not a simulation...

For example, the WW2 M82 APC (APEX in GURPS terms) does 6dx10(2) pi++ with a linked 6d+2[4d+2] cr ex.

That was calculated from a formula that gives all six dice their average value of 3.5 to, mostly, match the muzzle penetration value against rolled homogeneous armor.

Thus that round will penetrate DR 420 or rolling a 21 on six dice or ((6x3.5)x10)x2.  Dr 420 is 6" (152.4mm) of RHA.

But you could roll a 6 on six dice, do 60 damage and penetrate 120 DR or 1.7" or 43.5mm.

OR you could roll a 36 on six dice and do 360 damage and penetrate 720 DR or 10.3" or 261.3mm. 

Officially it penetrates 143mm or 5.6" or DR 393 or 6dx9(2) pi++.  At the muzzle.

Gun Stats gives it a little extra performance.

Realistically, that 393 points of damage should be at the muzzle and it should get smaller as the range increases.

But you can roll all ones for 6x10 at 1 yard and all sixes for 36x10 at 6,660 yards.

Again, game.

Balance between playable and accurate.

It's hard to strike sometimes.

The randomness of the dice and the chance at unrealistic results allows the game to account for anecdotal stories where people went, "Did you see that shit?"

A DR 4 M1 helmet will not stop even the minimum damage of a 7d pi K.98k, but there's examples where the round bounced off.  Result of a miss by two?  A miss by one is a torso hit (ever notice that all misses by 1 go low not high?)  The GM has to provide narration to what's going on to the players.

There's examples of "no way that will penetrate" going right on through.

Things tend to GURPS.  It's what I like about the game.

I don't wanna have to do the math that calculates the impact angle against the angle of the armor's slope and the velocity at that EXACT range.

Dice will suffice.