[Ultra-Tech] Optional rule for EM guns, feedback wanted

[PK]

David Pulver has been considering an optional rule for electromagnetic (EM) guns (GURPS Ultra-Tech, pp. 141-143). Ideally, this will make them more competitive with ETC slugthrowers. It's a significant change, though, so we'd like to see some people try it out and provide feedback.

1. Increase the basic damage of all EM guns by 25%, rounding up to the nearest whole die (or multiplier, for "6dxN" damage). Leave any "adds" as-is. For example, the Gauss CAW goes from 8d to 10d, while the Gauss Rifle goes from 6d+2 to 8d+2.

2. All 4mm rounds do piercing (pi) rather than small piercing (pi-). Yes, they're thin, but they're also long, and thus have considerable mass.

3. Drop the (3) armor divisor from all EM guns. Their standard ammo is fast but relatively fragile, which isn't great against armor. But keep reading . . .

4. Remove all restrictions on EM guns loading APHC, APDS, or APEP ammo -- so you can get that armor divisor back by loading one of these ammo types. The (2) armor divisor from APHEX warheads is now an improvement, not a downgrade. (See Ultra-Tech, pp. 152).

Example: A Gauss PDW (4mm) used to do 4d(3) pi-. This optional rule changes that to 5d pi, but if you're facing armored foes you can use APEP for 5d(3) pi- (which also gives 2x range but 10x ammo cost).

Example: A Portable Railgun (10mm) used to do 5dx3(3) pi+. This changes that to 5dx4 pi+, APEP makes it 5dx4(3) pi, APHEX makes it 5dx4(2) pi+ with a follow-up, and so on.

The net effect will most likely be users of EM guns loading expensive custom ammo (like APEP) to obtain an armor divisor. The increased basic damage will then give them better overall penetration, while the reduced piercing class (from the AP ammo) will keep the effects balanced with regard to larger weapons (7mm and higher) . . . At least, that's the idea.

Ideally, we'd love it if people could try using these "new and improved" Gauss weapons alongside ETC slugthrowers, and see how they stack up. Are there any balance issues? (Does it make them too good, for example?) Anywhere that the changes above seem to break or not make sense? David and I will keep an eye on this thread to answer your questions.

(PS: If anyone is using the "ETK" weapons from the Ultra-Tech designer's notes, please do not take those into consideration here. In fact, you probably shouldn't even use them in your own games. David has since disavowed them for being too overpowered and unbalanced.)

[Fred Brackin]

Preliminary remarks:

1. This helps some of the small caliber guns. The 4mm Gauss Pistol is compared in the text to a 15mm conventional gun but actually had wounding power inferior to a TL8 .380. Along with 2 that's better now but the text statement is still obviously false.

2. As a nitpick this is unlikely to be true. Most projections of Gauss weapons have them being fin stabilized like arrows rather than spin-stabilized like bullets. That would mean no tumbling. It might be simpler to turn all the 4mms into 5mms. Calibers in UT are already said to be notional.

3. This takes away one of Gauss weapons few strengths i.e. that you got APEP penetration for free. On the other hand it does make the system more regular.

4. has relatively little effect. APHEX is still limited to 10mm and up. So that's only 3 Gauss weapons 2 of which could already use it (Gauss CAW and Gauss Shotgun Pistol).

Overall it looks like a wash except for the people who were already using the 18.5 weapons. It's Christmas for them.

[PK]

Originally Posted by Fred Brackin

4. has relatively little effect. APHEX is still limited to 10mm and up. So that's only 3 Gauss weapons 2 of which could already use it (Gauss CAW and Gauss Shotgun Pistol).

Well, the idea is that most people will load APEP -- for the x2 range and to regain the (3) armor divisor -- not APHEX. The net effect if you assume APEP ammo as common is that Gauss ammo becomes 10x cost (not a huge problem, as it's pretty darn cheap), range doubles, basic damage goes up, and piercing class goes down.

[DouglasCole]

Originally Posted by PK

1. Increase the basic damage of all EM guns by 25%, rounding up to the nearest whole die (or multiplier, for "6dxN" damage). Leave any "adds" as-is. For example, the Gauss CAW goes from 8d to 10d, while the Gauss Rifle goes from 6d+2 to 8d+2.

this would be indicative of higher energy, since the GURPS basic damage formula is basically reduced to a function of KE and cross-sectional area (with various power laws). There's nothing inherently problematic here.

2. All 4mm rounds do piercing (pi) rather than small piercing (pi-). Yes, they're thin, but they're also long, which matters when tumbling through flesh.

There seems to be really one reason bullets tumble: they're butt-heavy and so they're more stable going backwards than point-first. This can be simple shape, but it can also be design.

Long, thin projectiles like this are almost always fin-stabilized, not spin-stabilized, which means that they will not tumble at all. In fact, this is one of the things that doomed the flechette project.

To increase the damage from pi- to pi you'd need to say that these projectiles were designed with fragmentation in mind. Not impossible, but not inherent, either.

3. Drop the (3) armor divisor from all EM guns. Their standard ammo is fast but relatively fragile, which isn't great against armor. But keep reading . . .

If the projectile is looking like "tank gun" fast (1500m/s or so) you might want/need it to be a pretty refractory composition like tungsten or DU in order to not burn up due to air friction. Those materials carry a (2) with them by most designs. A 4000fps/1300m/s steel projectile with a (1) or the not-used (1.5) would also be feasible.

4. Remove all restrictions on EM guns loading APHC, APDS, or APEP. The (2) armor divisor from APHEX warheads is now an improvement, not a downgrade. (See Ultra-Tech, pp. 152).

If the projectile is held in place or encased in a sabot (seems likely) than if you can make a projectile you can probably shoot it.

The weakest assumption is 2, which needs a lot more hand-waving.

[Refplace]

Making a higher TL weapon more competitive or powerful than a lower TL one seems good.
As for the options..
1. Sounds fine.
2. Small piercing can be attractive for law enforcement or even strategic military goals where low lethality is desired.
3. Lower damage but better armor divisors was a reason I liked gauss guns, though ETC and special ammos overcompensated towards the older tech.
4. Evens the field.


The spin vs. fin stabilizing for the darts seems to be a common concern as regards tumbling.
You could use larger and shorter bullets for when tumbling is desired. However wouldn't metal fins increase the size of the wound channel anyhow?
Seems to me like using Broadheads vs. Target point arrows.
So I could be way off but ti seems to me a flechette with, probably using spring tension to pop out the fins as it leaves the barrel would cause more damage than just a straight dart. To increase it though, why not add collapsing structure so as it hits it can flatten our our fragment. So you could add hollow point type ammo to the mix.

Also what about ball ammo?
And how about metal skinned plastic ammo for a less lethal round against unarmored targets? Maybe even make it biodegradable so you dont need surgery to remove the bullets.
And something like the liquid chemical option so you can shoot low, normal or high powered. I think a high powered option may be too powerful and the size of the barrel probably limits you but a low power option (again for law enforcement or small game hunting) should be doable.

Why do people like EM guns anyhow? We dont want to lose those features and just call them the same as ETC weapons.
To me, more shots per magazine, quieter shooting, higher ACC and higher penetration vs. injury were key features, especially going back to 3E.

[The_Ryujin]

Originally Posted by PK

David Pulver has been considering an optional rule for electromagnetic (EM) guns (GURPS Ultra-Tech, pp. 141-143). Ideally, this will make them more competitive with ETC slugthrowers. It's a significant change, though, so we'd like to see some people try it out and provide feedback.

1. Increase the basic damage of all EM guns by 25%, rounding up to the nearest whole die (or multiplier, for "6dxN" damage). Leave any "adds" as-is. For example, the Gauss CAW goes from 8d to 10d, while the Gauss Rifle goes from 6d+2 to 8d+2.

That actually works. My own ballistic damage hack as well as Doug's spreadsheet pegs a 4mm diameter, 42gr projectile moving at 5,000ft/sec as doing 8d+2 anyway.

Originally Posted by PK

2. All 4mm rounds do piercing (pi) rather than small piercing (pi-). Yes, they're thin, but they're also long, which matters when tumbling through flesh.

Rifle bullets tumble because they're bottom heavy and rather unstable in flight, long rod projectiles on the other hand are very stable and tend to have poor wounding. Though I guess you could hand wave it as designing the round so that their stabling fins are designed to rip away after impact in such a way they cause the round to tumble.

Originally Posted by PK

3. Drop the (3) armor divisor from all EM guns. Their standard ammo is fast but relatively fragile, which isn't great against armor. But keep reading . . .

4. Remove all restrictions on EM guns loading APHC, APDS, or APEP. The (2) armor divisor from APHEX warheads is now an improvement, not a downgrade. (See Ultra-Tech, pp. 152).

I already do this is a house rule. Though I think the 3 AD should be dropped for APEP rounds, instead they should be treated as APFSDS-U (GURPS High-Tech pg. 169) rounds minus the incendiary effect.

Originally Posted by PK

The net effect will most likely be users of EM guns loading expensive custom ammo (like APEP) to obtain an armor divisor. The increased basic damage will then give them better overall penetration, while the reduced piercing class (from the AP ammo) will keep the effects balanced with regard to larger weapons (7mm and higher) . . . At least, that's the idea.

Ideally, we'd love it if people could try using these "new and improved" Gauss weapons alongside ETC slugthrowers, and see how they stack up. Are there any balance issues? (Does it make them too good, for example?) Anywhere that the changes above seem to break or not make sense? David and I will keep an eye on this thread to answer your questions.

(PS: If anyone is using the "ETK" weapons from the Ultra-Tech designer's notes, please don't take those into consideration here. David has since disavowed them for being too overpowered and unbalanced.)

I should also note that ETC's modifier should probably be reduced from 1.5× to 1.3× and that ETK should instead be treated as being 1.5× based on what I've seen with development or real live ETC tech.

I'd also like to see some EM guns that weren't suck in the 1980's thinking of micro caliber flechettes, keep those for anti-tank work.

[McAllister]

Originally Posted by Refplace

And something like the liquid chemical option so you can shoot low, normal or high powered. I think a high powered option may be too powerful and the size of the barrel probably limits you but a low power option (again for law enforcement or small game hunting) should be doable.

Actually, this exists. UT p. 141: "Ammunition velocity can also be varied, exactly as for a liquid-propellant slugthrower (p. 139)."

Although, on this note, is there any interest in standardizing the number of rounds an EM gun can fire from a given battery? It seems silly to me that the Gauss CAW can fire 30 18.5mm rounds on a C cell, but the Gauss Shotgun Pistol can only fire 10. The Shotgun Pistol would be considerably happier if one battery could fire three magazines, or two high-power ones.

Which leads to wonder whether batteries are physically attached to magazines. It makes sense to do so, since emptying one empties the other, but clearly the Gauss Pistol's 0.5lb magazine can't include a 0.5lb C cell and, well, any actual bullets. What I'm asking is, does the number of actions listed in the table replace both the bullets and the energy cell (either because those are the same thing, or because the number of actions takes this issue into account)? Or does reloading a Gauss Pistol that needs both new bullets and a new cell take 6 actions?

Why do people like EM guns anyhow? We dont want to lose those features and just call them the same as ETC weapons.
To me, more shots per magazine, quieter shooting, higher ACC and higher penetration vs. injury were key features, especially going back to 3E.

Shots per magazine is a definite plus. High penetration is really big: the ratio of penetration to injury isn't as important to me. The ability to be quiet without an attachment, definite plus. High ACC, huge. I also like their simplicity compared to liquid-chemical propellant: I have the impression that an EM gun has fewer moving parts and simpler ammunition, and might be easier to keep working outside of UT infrastructure. I might not be able to make my own railgun, but it strikes me that TL8 should be able to keep one in ammunition, as long as I can recharge cells with something that plugs into a wall.

Oh, and the recoil. I don't think Rcl values particularly reflect this, but the kick caused by acceleration applied to the projectile over time should be smoother than a small explosion, yes?

Originally Posted by The_Ryujin

I'd also like to see some EM guns that weren't suck in the 1980's thinking of micro caliber flechettes, keep those for anti-tank work.

Do you mean railguns? Because I'd like to see some more railguns. TL9's Sniper Railgun is awesome, it' more accurate than a TL8 .50 caliber rifle shooting APEP rounds, which, besides firing in Boosted Velocity mode and having a longer range, is its primary advantage as a weapon. TL10's railgun, on the other hand, has to complete with Gauss weapons, loses three points of Acc despite having the same Bulk, gains a point of Rcl... I want to see a TL10 version of the Sniper Railgun, a railgun in the Pistol, SMG and Shotgun categories, and otherwise to get a feel for what the technology could do at TL10 if it weren't paying the high price that the Portable Railgun seems to pay for firing 10mm rounds.

[Fred Brackin]

Originally Posted by McAllister

TL10's railgun, on the other hand, has to complete with Gauss weapons, loses three points of Acc despite having the same Bulk,

10mm Gauss ACC has been made Errata. It's supposed to be 7.

As to why I like EM weapons I don't particularly except for the !8.5 ones. Claiming "low lethality" as a feature rather than a bug is wacky.

[Refplace]

Originally Posted by Fred Brackin

10mm Gauss ACC has been made Errata. It's supposed to be 7.

As to why I like EM weapons I don't particularly except for the !8.5 ones. Claiming "low lethality" as a feature rather than a bug is wacky.

There are plenty of times when you want to quickly and effectively disable a foe but killing them is not the most desired outcome. It is typically kill or be killed but if you can take someone out without killing them this is good.
Law Enforcement, hostage situations, fragile environments (like space stations), Bounty Hunting, etc. Even in a strategic military situation wounded foes hurt the armor more than dead ones. Unless healing is really easy of course.

[Anthony]

I would rather see a distinction between gauss and conventional weapons, instead of a purely cosmetic effect. Also, the main weakness of gauss rifles is really 'cannot punch through same-TL armor'. I like something like:

• Armor divisor becomes (2) for standard ammo. Ammo price is halved.
• Gauss weapons increase the armor divisor of all kinetic projectiles by 1 step. Gauss weapons can use all standard kinetic projectiles.

That means in the assault/battle rifle class we have:

• 7mm ETC Carbine: 7 lb, 1.5 lb/50 shots, 9d(3) pi-, Acc 4, Rcl 2. vs DR 70 tac vest, average injury is 4.25.
• 10mm ETC Carbine: 8 lb, 2 lb/50 shots, 10d+2(3) pi, Acc 4, Rcl 3. vs DR 70 tac vest, average injury is 14.
• 4mm Gauss Rifle:8.5 lb, 1.4 lb/60 shots, 6d+2(5) pi-, Acc 7, Rcl 2. vs DR 70 tac vest, average injury is 4.5

Personally, I would heavily nerf the 10mm rounds (probably reduce base damage to 6d and increase Rcl to 4), they're way too good for something that is inherently a terrible idea, but this thread is about gauss rounds.