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Old 02-12-2017, 06:02 PM   #1
Calvin
 
Join Date: Jan 2014
Location: Calgary
Default Inconsistent shotgun rules?

The average High Tech shotgun in GURPS does 1d+1 pi damage with a RoF of 3x9. Some do a little more or a little less damage, some have more or less pellets per shot, and some have a RoF higher than 3. But on average it's 9 pellets per shot at 1d+1 pi damage per pellet.

Now if you want to fire slugs you multiply the damage per pellet by 4 and increase the wound modifier to pi++. This means our "Average Shotgun" does 4d+4 pi++ damage with slugs. Which is the same as 5d pi++.

The problem arises when we decide to work backwards from the slug's damage value. There are rules for multiple projectile loads on HT172, and you get very different numbers if you apply them.

First let's say we're trying to go from a single 5d slug to some number of 1d+1 pellets. According to the adjusting damage box on HT166 we need a result of 1.15 to 1.42 after the NS multiplier is applied. If we pick 16 projectiles we get a 0.25x multiplier which gives us a result of 1.25. So we go from our 5d slug to 16 1d+1 pellets.

Second let's say we're trying to go from a single 5d slug to 9 pellets (same as default) and see what damage value we get for them if we use the table. The damage multipler for 9 projectiles is x0.33 which gives us a result of 1.65. If we take a look at the Adjusting Damage box we find that our new damage should be 2d-1.

Maybe after looking at the first point it would seem like you might get more pellets but reduce the wounding modifier, but then why is the damage value the same? And looking at the second point where would the trade off be there? More damage in exchange for... nothing?

Now you might point out that this might be abusing rules in ways which they were never intended, but what rules would you use to model bird shot, 00 or 0000 buckshot, or any of the many varieties of shotgun shells available? It's even more apparent if you take one of the guns from UT (though that book has it's flaws) where the baseline stats of the shotguns assume you're using slug ammo. Maybe mixing books is unfair, but you see the same thing if you take one of the large bore rifles and apply the shotshell rules there.

EDIT: I forgot about the rules about just how many projectiles can fit into any given shell. The max number of pi projectiles that can be fit into a 12g shotgun is actually 12, so the first example does change slightly. I guess it does allow you to get the same damage out of more projectiles by dropping to pi-. But if you just go for the max of 12 you end up with a shotgun that fires 12 pellets at 1d+2. The second example still stands as written.

Last edited by Calvin; 02-12-2017 at 06:37 PM.
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Old 02-12-2017, 06:36 PM   #2
DouglasCole
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Default Re: Inconsistent shotgun rules?

I took a look at a ground-up treatment of shotguns a while back on my blog:

https://gamingballistic.com/2014/01/...mo-house-rule/


I revsisited some of the the numbers some time later:

https://gamingballistic.com/2015/03/...cking-shotgun/
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Old 02-12-2017, 06:47 PM   #3
Calvin
 
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Default Re: Inconsistent shotgun rules?

Quote:
Originally Posted by DouglasCole View Post
I took a look at a ground-up treatment of shotguns a while back on my blog:

https://gamingballistic.com/2014/01/...mo-house-rule/


I revsisited some of the the numbers some time later:

https://gamingballistic.com/2015/03/...cking-shotgun/
I'll take a look at both of those. Is the version of your spreadsheet there the most up to date version? Or are there a couple different versions for different types of weapon?

EDIT: Looks like slug damage stays mostly as it is in the books, but when firing shot you either get more pellets, or more damage? Wound modifiers seem to be more sensible as well for the smaller shot projectiles.

Last edited by Calvin; 02-12-2017 at 07:07 PM.
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Old 02-12-2017, 07:56 PM   #4
DouglasCole
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Default Re: Inconsistent shotgun rules?

Quote:
Originally Posted by Calvin View Post
I'll take a look at both of those. Is the version of your spreadsheet there the most up to date version?
I haven't really touched THAT sheet since I wrote the post. I do remember doing the calcs again for that post, though.
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Old 02-13-2017, 06:30 AM   #5
Tomsdad
 
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Default Re: Inconsistent shotgun rules?

Quote:
Originally Posted by Calvin View Post
...

EDIT: I forgot about the rules about just how many projectiles can fit into any given shell. The max number of pi projectiles that can be fit into a 12g shotgun is actually 12, so the first example does change slightly. I guess it does allow you to get the same damage out of more projectiles by dropping to pi-. But if you just go for the max of 12 you end up with a shotgun that fires 12 pellets at 1d+2. The second example still stands as written.
It might be worth noting that in Tactical shooting it points out that at TL8 due to better propellants Shotshells can get more pellets than the basic listing suggest.

"from 9 to 12, from 12 to 15, or from 15 to 18" (TSpg78).

So there are other variables here making even the individual pellet size and overall damage calculation in HT a bit abstract. I think that's the reason why on HT pg172 it suggests going to real world figures first to calculate NP.

I did work up my own tables using the Multi shot rule in HT for 000 (9.1mm) to 3 Bird (3.56mm) shot sizes, and yeah you get a bit variation from the the Slug 4d+4 to 1d+1 examples. The table based stuff gets a slight edge but nothing too major IIRC.

Part of the problem here is in terms of effect in the system you have some hard thresholds damage rounding, fractional AD and Pi/Pi-.

Last edited by Tomsdad; 02-13-2017 at 07:10 AM.
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Old 02-14-2017, 09:17 PM   #6
Calvin
 
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Default Re: Inconsistent shotgun rules?

It seems kinda like the rules to convert from buckshot to slugs should be based off of the extremely close range rules. If you apply those rules as is to the nx9 RoF shotguns you basically get identical damage to a slug. You're penalized on armour, and I suppose range, since it's not actually a slug, but that does make sense.

I've been looking at the Parker Lifter from High Tech Adventure Guns for example. The standard 10G version has 11 2d-1 pellets and the slugs do 7d damage (Which by the way is amazing at TL5). The optional 8G version has 15 2d-1 pellets, but still does 7d as a slug.

On the other hand, if you use the extremely close range rules the 10G does 9d-1 damage, and the 8G does 12d damage.

Maybe I'll just slap a choke on the 8G and call it a day, or I fiddle with the spreadsheet to see what I get.
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