29 March 2015

That Thing

That long walkthrough of shotgun damage reminded me...

This is exactly the sort of thing people talk about when they say that GURPS is too complicated.

On the whole I tend to agree that GURPS is complicated, but I don't think it's overly complicated for what it's trying to do; and that's to be a core game for any genre.

What are the d20 rules for 20ga 2-3/4" 1 oz. #8 shot?  Once you calculate everything does it come even close to passing a reality check?

I remember in Twilight 2000 a couple of my players took the scarcity of ammunition to heart and decided they'd carry swords.  Seemed reasonable until I noticed that there weren't any rules for swords.

With GURPS I have rules for shotguns and swords, even though figuring out the shotgun load is complicated.  Luckily it's only complicated once!  After you go through the complicated process of figuring out the stats, you write them on the character sheet (or make your own weapon table) and it's done and now it's on one simple table.

Still, sometimes the rules as written are awkward.  Like in the #8 shot problem: it seemed as if a t-shirt made you immune to the effects of a 20ga shotgun less than three feet from your chest.  You've got to notice and or remember the blunt trauma rules or that t-shirt is armor!

Luckily, this is the first time any debate about shotgun damage has ever happened to me.  I really don't get to play very often because I've never managed to locate GURPS gamers around here.

It came up because I have a project for my amusement.  If a meatspace friend shows me a gun they own, I write up GURPS stats for it.  Marv is the reason I have stats for 16ga and 20ga shotguns; because he inherited a Winchester Model 12 in 16ga and a Remington 870 Express in 20ga.

I only plumbed the depths of small shot because the GURPS shotgun damage default assumption is 00 Buck.  They don't seem to make 16 and 20 in 00...  So I needed stats for ammo that was actually made for the guns, that meant learning the rules.

It's never come up in game because my players have always done the damage - rate of fire - capacity - weight calculation and noticed that a shotgun is pretty darned heavy for the number of shots it holds and that each shot is heavier than rifle ammo and they're pretty slow to reload.  When a .30-30 is just as socially acceptable, does the same damage as a 12ga slug (not quite since the shotgun gets a p++ instead of pi but they're both 5d) out a lot farther, and is lighter overall despite having the same reload times...  They gravitate to the rifle.

Take away social and legal constraints and out come the assault rifles!


  1. In my GURPS Metro setting, I've noticed just the opposite. When everything's pistol caliber or a shotgun, shotguns with slugs become the heavy hitters. For those who aren't combat specialists, why NOT grab a shotgun and take advantage of that huge bonus to hit? Sure, ammo's heavy if you're expecting to be doing a lot of fighting, but for the merchant running off the odd bandit or hostile critter with the help of some hired guns, a cut down double barrel 20g full of buckshot works just fine for the not-very-well-trained. Still, in most normal settings, the benefits of my rifle (particularly where I'm trying to guide my players towards effectiveness) is summed up by my Choose Your Weapon quiz.

    They do have rules for 00 buck for 20g, the Ithaca Auto & Burglar 20g on High Tech p104. Does 1d pi, same range as all the other 00 buck, 7 pellets per shell. They DO note that 00 buck is hard to come by in 20g, and the smaller round would be more common.

    1. The stats for 20ga 00 buck don't matter if there's no ammo in that shot size. Wade into Midway or Brownells you're going to find that nobody loads even 0 buck. I'm not finding historical references to 00 for 20ga either, the intent of the round was to be upland game.

      The biggest shot size I found was #1 buck, which is still "birdshot" according to High Tech p. 173. We're going to start with the Remington Model 17 from High Tech Pulp Era Guns Volume 1 p. 25 and p. 27 because it's not a sawed off gun; 00 buck is 1d+1 pi. Now we take a trip around the bloody world... We need to figure slug damage first, which is on High Tech p. 166 The 1d+1 pi becomes 5d pi++ (I fudge it to 5d-1 pi++ because 20 is less powerful than 12). We take our 5d-1 pi++ over to High Tech p. 172 and calculate NP and NP. NS is 0.33 because there are 9 pellets (NP 9) in a 2-3/4" #1 buck load. Moving to the next page we hit Shotshell and see that we multiply slug damage by NS. By using the convoluted process from High Tech p. 166 5d-1 becomes 1d+2 pi, but because #1 is birdshot as defined on High Tech p. 173 it becomes pi- and gets (0.5) armor divisor.

      So 1d+2(0.5) pi- per pellet and x9 shot multiplier instead of the x7 for 00.

      So, yes I am aware of High Tech and how it works, thanks.

      When I mentioned "What are the d20 rules for 20ga 2-3/4" 1 oz. #8 shot?" I was referring to *DEE TWENTY* not GURPS, look I even said so... And yes, I've seen d20's miserable excuse for firearms rules and its solid anchoring in Dungeons and Dragons is clearly visible.

      Availability of ammo is world specific and that definitely would change the balance of choice. In on T2000 adaptation to GURPS the difference between older 5.56 guns with 1:12 barrels and newer guns with 1:7 barrels mattered because the ammo supply wasn't sure.


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