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Old 09-01-2021, 02:24 AM   #1
GURPS Fox
 
Join Date: Jun 2020
Default Guns! Guns! Guns! and GURPS

So, I've been told that Guns! Guns! Guns! would be far better for me to design my weapons than Vehicles, and I've got a question: Are there any tips and tricks on doing this because I've been using Vehicles 2e for so long that I've gone complacent. I also have the old spreadsheet, if you're going to ask that.

This is largely due to one of my settings having pistols that fire 16-gram bullets at 1250m/s (or, about 0.50BMG kinetic energies) at the minimum, and gets more insane from there. So far I've been doing decently but it's slow going due to the fact that my excel skills aren't the sharpest.

I've been building Google Sheet workbooks to make the process more automated for entire arsenals:

Prototype (so far) of Guns! Guns! Guns!/GURPS hybrid sheet: https://docs.google.com/spreadsheets...it?usp=sharing (please comment)

Purely GURPS Sheet: https://docs.google.com/spreadsheets...it?usp=sharing (also, please comment)

Also, if someone back-engineered how the guns in the 4e books are designed, I would like to see them. :)
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Old 09-01-2021, 03:21 AM   #2
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Default Re: Guns! Guns! Guns! and GURPS

That's more like 2/3rds of the muzzle energy of a .50 BMG. It's momentum is about half that of a .50 BMG round though, so recoil energy will be 'only' about a quarter if fired from a weapon of identical weight. Of course it's about 2.4 times the momentum of a 7.62x51mm NATO round, and thus about six times the recoil energy. Without, ah..., 'heroic' recoil reduction systems that's not a handgun round.
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Old 09-01-2021, 05:35 AM   #3
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That's more like 2/3rds of the muzzle energy of a .50 BMG. It's momentum is about half that of a .50 BMG round though, so recoil energy will be 'only' about a quarter if fired from a weapon of identical weight. Of course it's about 2.4 times the momentum of a 7.62x51mm NATO round, and thus about six times the recoil energy. Without, ah..., 'heroic' recoil reduction systems that's not a handgun round.
The setting had a period of time where everyone was having their soldiers run around with HMGs as their assault rifles because nothing else could reliably penetrate the armor of various power armor systems (be either armored combat exoskeletons or what would be considered the 'genuine article' by many). By the time of the setting's 'present', everyone is running around with an ablative armor scheme that requires a certain amount of energy to ablate ala Battletech armor.

It also doesn't help that the average human in the setting is described as "Halo SPARTAN-IIs and Battletech Elementals having kids and augmented them with Ghost in the Shell-style Cybernetics".

Yeah, it's that sort of setting.
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Old 09-01-2021, 09:03 AM   #4
Fred Brackin
 
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Default Re: Guns! Guns! Guns! and GURPS

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Originally Posted by GURPS Fox View Post
So, I've been told that Guns! Guns! Guns! would be far better for me to design my weapons than Vehicles,:)
It'll be more complicated anyway. That'swhy I looked at GGG very briefly many years ago and set it aside. What youi want can probably be done in Ve2 though.

To get 13.5 D out of 9mm you'll need Electrotthermal and a barrel that's 720 mm long so that's not much of a "pistol" even for an SM+1 cyborg. Empty weight is 1215 lbs and Recoil is -4 and MinSt is 43.

I'd design another way to get around your armor. GGG might not understand the effectiveness of HEAT warheads.
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Last edited by Fred Brackin; 09-01-2021 at 09:13 AM. Reason: Yes, I screwed up the math the first time and came back and fixed it
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Old 09-01-2021, 03:25 PM   #5
GURPS Fox
 
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It'll be more complicated anyway. That'swhy I looked at GGG very briefly many years ago and set it aside. What youi want can probably be done in Ve2 though.

To get 13.5 D out of 9mm you'll need Electrotthermal and a barrel that's 720 mm long so that's not much of a "pistol" even for an SM+1 cyborg. Empty weight is 1215 lbs and Recoil is -4 and MinSt is 43.

I'd design another way to get around your armor. GGG might not understand the effectiveness of HEAT warheads.
Conventional guns in my setting are all electrothermal chemical guns outside of the odd BilPro gun. Using stuff like HEDP/HEAT isn't exactly going to work due to armor's effectiveness against AP (which is similar to how a metal foam composite did better against a 0.50cal AP round than a 0.50cal ball round). In gameplay terms, the armor is an ablative laminate with a 1+ hardening (or, in gameplay terms, all armor divisors are halved, rounded to the nearest whole number, i.e. (2)s become standard, (3)s become (2)s, and (5)s become (3)s).

The thing with V2e is that ETC weapons aren't much improvement to conventional rounds, something that goes against how my setting's weapon development went (to give an example, there were a few decades where anyone who was anyone had to turn their AMRs/HMGs into assault rifles because that's the only way to penetrate the armor in any reasonable time period). That and it gets really bad with EM guns where they take a complete backseat to DEWs (even with the 5x space range rule, EM guns simply suck when compared to DEWs and my setting has spaceship EM guns work as a short-range, cheap (in terms of energy and cost), but very effective backup to DEWs) in general.

It should also be noted that the pistol is achieving this with an 18cm barrel (the original markup using V2e rules had a very short barrel, and I reasonably assumed that this meant a barrel caliber of less than 30, so I picked 20)...
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Old 09-01-2021, 04:08 PM   #6
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Default Re: Guns! Guns! Guns! and GURPS

Ve2 says a 'very short' barrel is 10-19 calibres (sidebar, VE99). That ETC 'only' gives x1.5 damage (sidebar, VE111) is pretty reasonable - that's x2.25 muzzle energy along with a considerable reduction in ammo weight.
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Old 09-01-2021, 04:24 PM   #7
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Ve2 says a 'very short' barrel is 10-19 calibres (sidebar, VE99).
Completely missed that.
Quote:
That ETC 'only' gives x1.5 damage (sidebar, VE111) is pretty reasonable - that's x2.25 muzzle energy along with a considerable reduction in ammo weight.
Thing is, ETC propellants have a velocity range of 2km/s to 4km/s if what I've heard is true. The projectile would be the same mass -or even heavier- as well, giving high levels of capability.

To give you an idea, conventional propellants can only achieve ~1.7km/s at best.

The setting has armor 'catching up' to offense, mind you...
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Old 09-01-2021, 04:47 PM   #8
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Completely missed that.

Thing is, ETC propellants have a velocity range of 2km/s to 4km/s if what I've heard is true.
Unless you're just dumping massive amounts of energy into the propellant, mostly what ETC lets you do is keep chamber pressure more consistent, which gives you the same maximum out of a shorter barrel.
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Old 09-01-2021, 05:01 PM   #9
GURPS Fox
 
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Unless you're just dumping massive amounts of energy into the propellant, mostly what ETC lets you do is keep chamber pressure more consistent, which gives you the same maximum out of a shorter barrel.
From what I understand, ETC is to give you more velocity with consistency as a close second. This is largely -from what I understand- due to the fact that our current propellants have reached their peak in terms of performance (1.7km/s is roughly the top of the rankings in terms of velocity in non-BilPro/ETC guns).
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Old 09-01-2021, 05:07 PM   #10
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To give you an idea, conventional propellants can only achieve ~1.7km/s at best.
Current Russian and German tank guns manage ~1800 m/s, and the Russians have a 150mm gun that supposedly manages just under 2000 m/s.

VE2's ETC rounds with 50% more energy from bullets of less mass would therefore be producing muzzle velocities in excess of 3000 m/s, well within the velocity range you give.
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