10 mm rounds

[Lexx]

Ok, now that I've gotten the issue of range for a 10mm snubber settled, I'd like to know something else:

In gurps bullets ranging from .40-.60 calibur get a bonus on damage due to size.

Now, does a 10mm rond could as a .40 calibur and get the extra damage?

This one sheet I have says yes, dr. kroom said no, I can't get an official answer. Anyone have a calibur converter to convert metric to standard caliburs?


BTW, according to gurps, a bullet less than .34 calibur get a minus 50% damage, from .34 to .40 it gets no change, from .40 to .60 it gets plus 50% damage and over .60 calibur boudles damage. I think a 10mm round is at the edge of being a .40 calibur and have conflicting information on whether or not it gets extra damage for it's size.

 

[TJP]

AFAIK, caliber (in this case) is equal to an inch, e.g. .44 caliber is .44 inches. Therefore a 10mm round equals .39 caliber (10/25.4 = 0.3937) and thus does *not* get the damage bonus if you're being strict to the .40 to .60 caliber limit.

I'll check how the GT 1st ed lists the snub's damage when I get home.

 

[Slink182]

I'm not familiar with GURPS, but am with bullets and guns.

You will need to clarify what kind of .40 cal you're referring to. A .40 musket ball will be significantly different from a .40 cartridge round. However, since you specifically mentioned 10mm and .40 in the same sentence, I'll assume that the .40 you're referring to is the .40 Smith & Wesson.

The .40 S&W is a cut down cartridge based on the 10mm round. It uses the exact same slug, but in a shorter brass casing. This was for the purposes of getting a more "friendly" round to fit in small framed self-loading pistols (the 10mm required a much larger frame due to bullet size and power). In terms of power:

(lower) 9mm, .40 S&W, 10mm, .45 ACP (higher)

So it follows that, if your .40 S&W (technically the "weaker" round) is getting the extra damage bonus, then the 10mm should also.

 

[Lexx]

Actually I'd think the 10mm in GT would get a bonus because it's meant to stop a man (or whatever) while not being too dangerouns to the ship it's fired in.

So it might be deisgned with low velocity and limited range, but given a large enough size to make a better wound channel to stop a man thur bullet size.

That would explain why it was 10mm and not the more common 9mm.

 

[Malenfant]

If Dr Kromm says no, AFAIK that IS the official answer. IIRC he's the guy that has final say on how official rules work in GURPS.

 

[TJP]

OK I checked GT 1e and it doesn't seem to use Bullet-size modifiers. So no help there. Then I checked GURPS High-Tech (3e), which was the first book I remember seeing this modifier in. On p.7 it lists wounding modifiers (note that these affect wounding only, not penetration) and it converts those .40-.60 calibers to 10-15mm. So according to High-Tech 10mm rounds get the +50% damage modifier afterall. Go figure!

Also, on the weapon tables of HT there are few .40 S&W firing pistols and they do "2d+" damage, i.e. (2d6-DR)x1.5, further confirming the +50% damage mod to 10mm rounds.

However, to complicate things, Snubs don't fire ball ammo, but HE and HEAT (plus tranq), and these are a whole different ballgame altogether. If memory serves, an explosion inside flesh does x5 damage in GURPS (BTW, base 10mm Snub damage when firing HE is "1d Exp."). I have no idea do you apply bullet-size mod to this as well or not (I'd guess not). Also I don't know what possible use a 10mm HEAT round might have.

Oh well, did I manage to completely confuse everyone...

 

[TJP]

Originally posted by Malenfant:
If Dr Kromm says no, AFAIK that IS the official answer.

I'd like to go with this as well, but then High-Tech contradicts him (or he contradicts High-Tech, whatever), at least if we're talking about 10mm ball ammo, which I'm no longer sure we are. I guess it's time for me to go to bed. Good Nite!

 

[Slink182]

OK - my original comments on .40 S&W vs. 10mm assumed ball ammunition. I never took into account 10mm snub ammo.

I would suspect that, since snub ammo is generally low-V with a HE/AP payload, there is a high likelihood that the damage bonus would NOT apply. Damage would be from the payload itself.

Imagine: I fastball a baseball at you at 92 mph. That sucker is going to HURT when it hits. Now consider the same ball travelling at, say, half the speed - sure, it'll still hurt, but not as much (no "extra damage"). But it the ball was designed to explode when it hit you, well, that's a different story.

btw, is this Dr. Kromm (no clue who this guy is) by any chance related to E. Gary Gygax...?

 

[Malenfant]

Dr Kromm is Sean Punch - he's the rules guru, in charge of maintaining the GURPS system at SJG.

I'd hope that any inconsistencies will get fixed in GURPS 4e...!

 

[Lexx]

Actually, GT 2e does have a solid shot for the 10mm snub, called "ball", that does 1d+1 cr. damage.


They no longer have the HE round, and the HEAT round does 3d(10) exp. damage.

So it was the 2e ball round I was asking about. According to some, a 10mm round DOES count as a .40 calibur, tho dr. kromm wasn't sure it did. A gurps sheet I have listing a lot of tables lists is as a .40 cal and therefore getting 1.5 damage, and according to a guy here another gurps book lists it that way too.

I'm leaning towards making it a 1.5 damage round just to give the thing some more effect...

 

[Lexx]

Ok, according to the official combat flowchart fro SJG, there is, in fine print, a note saying that 10mm round DO count as large rounds and get the 1.5X damage bonus.

This seems fine with me as the round is, as I said, meant to be a man stopper without having a lot of velocity to wrech machinery and pierce hulls with.

 

[Badbru]

Hi Lexx. I turned my place upside down looking for my Gurps Cyberpunk, alas to no avail, as I have memories of a .40cal machine pistol in it that had the x1.5 damage. From my (limmited) understanding of bullets 10mm and .40cal are near enough to exactly the same "diameter" that I'd think they'd get the same bonus.
There are two schools of thought on this though... 1) damage is proportional to veleocity.
TNE's Fire Fusion & Steel has a 1 page writeup on weapon damage that follows this philosophy. Worth a read if you can get it. or...
2) damage is reflected by diameter...
I was reading somewhere about the US civil war era black powder weapons, they didn't have huge velocities but they did have sizable rounds like .40 .45 .50 and .55 cal balls They moved slower than say a 5.56mm Nato round but the wound channels, and more importantly, the bone shattering they did made them horrific weapons.
For this reason I'd go with the x1.5 damage whilst maintaining a low penetration capability.
Hope it helps.

 

[mike wightman]

Badbru, you're memory is correct. Gurps Cyberpunk does list a .40 calibre caseless round machine pistol with a damage mod of x1.5.

 

[BrennanHawkwood]

The sidebar "Damage Modifiers vs. Flesh for 10mm or Larger Rounds" on pg 181 of GURPS Vehicles 2ed, indicates that the modifier is applied for crushing damage projectiles of 10mm (.40 caliber) or larger. It is pretty clear that it is 10mm or larger.

 

[Straybow]

Yes, but snubs are so low in velocity that they should not get the damage multiplier. I suspect Dr. Kromm was ruling on the snub rather than the caliber.

 

[Lexx]

Well, to be blunt about it without the damage mod the snubber would be useless unless firing HEAT at a hard armored target, so I'm going with the damage multiplier.

 

[BrennanHawkwood]

The way I read the rules in GURPS Vehicles is that that modifier is based purely on the size of the round with the assumption that the round is being propelled at speeds appropriate to a firearm. IIRC, the actual speed of the round is taken into account in the base damage (by making the weapon a Low Power, very short barrel weapon for instance). I think the idea is that rounds of that size moving at speeds produced by firearms will do more damage than smaller rounds moving at an equivelent velocity even if that velocity is relatively low for a firearm.

How realistic that is, I couldn't tell you, but it makes some sense logically and jives with most of the 'evidence' from other sources and Lexx's analysis of the damage potential of the snub pistol.