GURPS ULTRATECH ballistics?

[hal]

Originally Posted by HANS

No. The total weight per shot of the 4.73×33mm DM11 is 5.2 gram (0.01146 lb, or WPS 0.011 as per HIGH-TECH, p. 176). This is per Seel DIE G11 STORY (1993) and Kersten/Schmid HECKLER & KOCH (1999). I'm assuming both are not available to you, both being in German. The former is the ONLY book on the G11 and nothing but the G11. The latter is the official history of H&K. The authors of both had access to the weapon and ammunition.
Further, you are reading Hogg MILITARY SMALL ARMS DATA BOOK (1999) wrong. The "186" on p. 275 line 2 column 8 is NOT the weight per shot, but the bullet diameter in 1/1000 inch.
Frankly, this is also obvious from the facts. If the bullet weighs 3.2 g, it is extremely unlikely that the whole caseless cartridge weighs 12.05 g. Because then it would weigh just as much as a cased cartridge (compare the 5.56×45mm M193, which has a 3.63 g bullet and weighs 11.79 g overall). Caseless cartridges generally halve overall weight ...

Cheers

HANS

Yup, my bad, I figured that out later, but never corrected my original post. None the less, the actual weight of the bullet listed for the G11 ammunition is still listed as 49 grains or 3.175 grams. Again, it boils down to how two different reference books quote different values. I don't mind using what you say is a more definitive reference book, but without access to the books, I can only go by the reference books I do have. What I did note however, is that whereas your book lists it as 5.2 grams works out to 80.25 grains. It seems really odd that there is that much of a difference between the round weights in grains. The bit it lists within the book states that the G11 caseless round underwent an evolution - so where you're going with 5.2 grams versus the 3.175 might indeed, but different rounds under development. Without a translated copy or a translated list of the various rounds under development - I'd have to go with what I can get my hands on when I attempt to work the numbers.

Right now? I THINK I have what Doug started out with (his is FAR more exacting in the data you need for the damage values and the like. My method simply relies upon Bullet Mass in grains, Velocity in feet per second, and bullet diameter in inches (as those are the values my books express things in). The half damage values I may (repeat MAY) have a handle on, and am waiting on Doug to confirm whether or not I got that right or not based on the numbers I used for aspect ratio, diameter, and bullet mass for a 10mm Auto pistol cartridge.

When I went to try and dig up stats on a 10mm gun for use in my cyberpunk campaign, the Glock 20 was the only listed weapon I could find in GURPS HIGH TECH via the search function in the PDF. Unfortunately, the stats for the Glock 20 as do many of the other Glock pistols, lack a half damage range. One can probably fudge those values if you can find other guns using the same cartridges (it is likely they will be close in value).

Long story short? I wouldn't bother with this if there were more samples of guns (hint hint hint) :)

GURPS HIGH TECH is nice, and the Adventure Guns for Old West campaigns was really nice. As mentioned before, when I created an Excel database of real cartridges with real data (bullet weight in grains, velocity in feet per second, and bullet diameter), the damage values in the spreadsheet almost matched the damage values for your guns in Adventure guns. I think maybe one of them didn't match yours.

I know you've already said that unless we use YOUR formulas and the like, we're not going to get the same values as what you do. I don't mind that. Until that formula is made available (and I'm not expecting it ever will), Doug's approximation seems reasonably close that I'm not worried about it. And if the data from real guns and cartridges allow me to stat up a Spanish gun, or a Belgian Gun, or a Japanese gun that isn't listed in GURPS HIGH TECH, then I'm happy. I don't want to have to slave over each and every "gun" that I want to stat up for use in the game. If the spreadsheet can do that quickly enough, then it is good enough for me. :)

Now, for the question that brought me here just now...


If we use the formula DmgPts = average damage for the weapon in GURPS damage values, it works out to the number of dice is equal to Int(DmgPts/3.5).

The "+X" modifier to the dice will generally be either -1, 0, +1, or +2.

So in game terms? If the remainder after the Int(DmgPts/3.5) is around 2.5, it adds 1d6-1 to the initial "integer" value of DmgPts/3.5.

If the remainder is around 0, then it should be modifier = 0
If the remainder is around 1, then it should be +1
If the remainder is around 2, then it should be +2

So, where are the "boundaries" for each category?

Remainder is between -.25 and +.25 for +0?
Remainder is between .5 and 1.49 for +1?
Remainder is between 1.5 and 2.24 for +2?
Remainder is between 2.25 and 2.75 for 1d-1 added to the original value?

That's the final thing I'm working on addressing before I set up my spreadsheet using Doug's formulas that determine 1/2 Damage range, Max Damage Range, Damage Points, and Dice Damage plus modifiers.

Everything else - weapon weight, weapon length, maybe barrel length (affecting accuracy perhaps?) and so on should be reasonable.

If you already have cartridges detailed (like the 9mm Parabellum), then any other gun should generally match those already published (In general, not absolute!). If the velocities at the muzzle are close enough to each other, then for all intents and purposes, their half damage ranges etc should be similar based on already published data.

Now, I KNOW that a gun that is rated for say, .40 cal bullets will have different damage ratings simply because not all bullets for the .40 gun will have the same bullet weights, bullet shape, or even muzzle velocity. Apparently, GURPS is too granular for that (or maybe not).

So, will I spend weeks developing Cyberpunk rated conventional guns for 10mm? Probably Not. Will I create fake cartridges using GUNS GUNS GUNS for bullets that might be rated as 11.5mm rounds? Possibly. Will I possibly translate CP2020 guns into GURPS analogs? Possibly. But, I would hate to do it pulling numbers out of thin air without any understanding of the process (which is why I picked up GGG by Greg Porter in the first place). It is also why I looked more closely at Doug Cole's spreadsheet more closely (and will look at the other that was mentioned because it does a decent job of estimating real life values based on input by the spreadsheet's author.

I just wish that GURPS ULTRATECH had included more handguns, and conventional handguns as well. If we've not gone to Caseless even though we're now VERY close to 2020 (and past CP2013 by some 4 years now!) chances are good that in the next 30 years, we might NEVER use caseless.

Now, if the formulas used to create/craft guns for GURPS HIGH TECH are not sufficiently proprietary that it would be worth creating a "Gun design" Pyramid Article, I'd buy it in a heart beat. GURPS VEHICLES for 3e had gun design rules. I've seen (but not been tempted by) the energy gun pyramid rules - so why not conventional gun rules? We've got rules from the Pyramid for designing armor (which I've used for my Cyberpunk campaign already).

*sigh*

I know I'm tired, and possibly not saying this as diplomatically as I could perhaps say it - but I'd really like to see the tools to create "things" for our Sci-fi campaigns. I recall creating my own "gun rules" before GURPS HIGH TECH first came out, using AFTERMATH rules and GURPS 1st edition (or was it Second edition by then?). That is what got me hooked on GURPS back in 1986 and kept me playing since then. If I didn't have the tools outright - I could cobble them up somehow. So, thanks to Doug and others - I'm going back to cobbling up some GUNS. ;)