[Ultra Tech] Near-future armored combat/mecha system ideas

[seasalt]

I've been wanting to run a near future action game emphasizing urban combat with tanks, power armor and so on, with more of an emphasis on heavily-armed paramilitary groups like private military corporations, criminal syndicates and law enforcement rather than a regular military (with army units that do exist being limited in their ability to respond plot and setting reasons). My big inspirations are classic 90s anime like Patlabor, Ghost in the Shell and (especially) Dominion Tank Police.

You might think there would be better systems for this than GURPS, but there really aren't a lot of mecha systems out there, and almost none that don't assume a kind of 'sword duels with lightsabers' style (Battle Century G, Lancer, etc.). In any case, I think that the realistic-ish approach GURPS takes to personal combat has its advantages here, too.

The idea is that sometimes the characters will be controlling armored fighting vehicles - which, compared to modern day tanks, tend to be a lot faster and more agile... highly mobile, but more lightly armed and armored, often resembling things like the tachikomas of GitS... wheeled legs, omnidirectional ball wheels (like the titular 'Tank Police' use) and so on allow such fighting vehicles to navigate narrow spaces in urban areas. Something like the "light tank" from the book would be the sort of tank a national military would deploy in open terrain, but, since most objectives worth fighting over are in urban areas, there is more of an emphasis on lighter, cheaper, more nimble vehicles.

Both weapons and armor are lighter, but beyond light armor and evasion, AFVs rely on point defense weapons to survive. Which is a bit of a problem since, uh, Ultra-Tech doesn't give any rules for point defense whatsoever.

That's fine, though, because if it's going to be happening a lot, I wouldn't want to be doing attack rolls and damage rolls against each individual projectile. Instead, I think the thing to do is treat these cyberpunk armored cars and things more like characters, and allow them to use variations of the parry, block, and feint rules against ranged weapons. Block would represent active defenses (e.g. point defense), while parry represents passive defenses like jamming, decoys, and smoke. Dodge represents both evasive movement as per the standard, and also stealthiness, use of cover, and situational awareness to avoid completely exposing oneself. But before we talk about defenses, let's talk about what kind of weapons are going to be used.

Using the Ultra Tech weapons as a baseline, the most common offensive armaments for an IFV or armored fighting vehicle would be the 25mm assault cannon, a multi-barreled low-velocity gun equivalent to a 64mm mortar box, or a missile pod equivalent to a 64mm MLAWS with a ROF of 6. Bigger ones might sport a high-velocity 60mm cannon that deals... eyeballing it here... 6dx10 (or just 6d on the decade scale, which is what we'll be mostly using), ROF 2, Recoil 3, 2000/9000 range. Flexibility of ammo is key, since even the 'bad guys' generally want to use only as much force as necessary and will pack non-lethal munitions to use on unarmed or lightly armed targets. But when it comes to an enemy AFV, the main choices are shaped charges for most weapons, as well as SEFOP rounds with top attack capability for the missiles, and APDS for cannons. Fairly standard - these vehicles will usually have an average of something like 260/160 laminated armor and otherwise resembling the "Wheeled ATV" but trading a point of stability for handling (+0/3) , with cheaper models lacking EMA. In other words, a single good hit is enough to cause crippling damage and possibly disable the vehicle outright. Compared to the tanks from "High tech" which have thick armor on the front plate but a weak top and bottom, these vehicles would have just as much sloped armor on the top as on the sides, due to the profusion of top-attack ordnance.

First, a quick note on automation. Because games about robots fighting eachother are lacking in drama, in this setting, "computer-controlled" combat vehicles are tightly restricted and mostly illegal, limited to only a few national militaries (including ordnance like the 'genius missile' from Ultra-Tech - swarms of those are what made the recent international conflict so bloody and destructive). Even there, use of pilotless vehicles or computer-controlled offensive weapons is something of a "nuclear option" with severe diplomatic consequences, due to said recent war. So there's your excuse for why trained pilots, gunners and commanders are still needed. 'Combat drones' do exist and are common, but they're remote-controlled by human operators, usually over a relatively short distance so jamming-proof control methods like laser comms can be utilized. And, of course, criminals and terrorists don't care about these laws and will gladly use any combat robots they can acquire or make.

Which brings me to point defenses. To make things interesting with such lethal weaponry we'll assume that active defenses have temporarily gained the upper hand against weaponry, relative to to the first quarter of the 21st century, and AFVs have a hard time getting a hit in on one another due to sophisticated computer-assisted point defense systems (those aren't "offensive weapons", you see - a legal loophole). Most of these would map pretty closely to existing weapons in Ultra-Tech:
Semi-portable laser (for light vehicles) or point-defense laser (for heavier ones)
Tactical microwave disruptor
'CWIS style' 7mm minigun
15mm Splat gun with shot-shell ammo, a.k.a. 'Flechette pod'
25mm payload rifle with high-explosive ammo set for proximity detonation, a.k.a. 'Interceptor gun' (which is pretty much what the 'Griffin 3' light tank being developed for the real world U.S. army is intended to use - I intend to stat out an upgraded version of the Griffin as one of the more ubiquitous combat vehicles in the setting)

Rather than working out modifiers for shooting down each individual type of projectile and rolling damage, these computer-controlled defensive weapons systems are treated as an active defense - specifically, a block. Each can only defend against a single attack per turn, but, like dodge, they can be used against rapid fire attacks, and stop a number of hits equal to their margin of success, by default. Their block is based on the skill of the computer program controlling the weapon in defense mode, not the gunner or commander (though a skilled commander is still important to manage them; see 'Feints' later on).


The average one of these will be controlled by a weak dedicated AI with complexity 5 (an IQ of 8, the "Fast" modification to give it enhanced time sense), also running a specialized variant of "silhouette" and a skill+1 targeting program with tracking up to 100 targets, as well as a skill level with its weapon of attribute+5 (so, 13). This requires a hardened high-capacity computer weighing 20 pounds to run, so small vehicles are limited in how many such defense systems they can mount. To the extent they're treated as a character these also have a limited version of altered time rate that allows them to aim and fire instantly, and since they're slaved to a sensor system, the accuracy bonus is doubled (to a max of +9). The effective skill and block value for each of these weapons is listed below, along with their advantages or limitations:
[continued in next post]

[seasalt]

[part 2]

Laser: effective skill 41 (43 for semiportable), block 23 (24 for semiportable)
Advantages: Usable against all projectiles, unlimited ammo. Doubles as an effective anti-infantry and anti-drone weapon, and can snipe sensors and other small weak points on enemy vehicles.
Disadvantages: Expensive and maintenance-intensive. Suffers penalties due to smoke/rain/dust/fog. -4 to block sabots and other solid shot, -2 to block cannon shells and other high-velocity projectiles. Some missiles may have ablative coating giving a -2 penalty. Double penalties from feints. Semi-portable laser can't block high-velocity projectiles (works on 64mm or smaller missiles, grenades, and mortar shells only). Malfunctions on 16+; roll HT. On success, overheats for 1 minute. On failure, burned out until repair. On point-defense laser, Malfunction decreases by 1 each consecutive turn it is used to block, until it spends 2 turns cooling off. If the heat radiator is sealed off, malfunction chance goes up twice as fast. The radiator is size -2, DDR 2, and DHP 2. If it is destroyed, the laser automatically malfunctions on every subsequent shot.
Microwave disruptor: skill 41, block 23
Advantages: Excels at targeting volleys of multiple projectiles: each margin of success on the block stops 2 extra hits instead of 1, unlimited ammo, no overheating, halve penalties from feints. Doubles as a very effective anti-drone weapon.
Disadvantages: Cannot stop sabot or solid shot projectiles at all. -6 to block cannon shells and other high-velocity projectiles, some projectiles may be EM-hardened giving a -2 or -4 penalty. Gives a -4 penalty to all attacks and perception rolls on each turn following a turn in which it is used to block (if used to defend a friendly target, this penalty applies to both the vehicle the microwave is mounted to, AND the friendly vehicle being defended).
CWIS 7mm minigun: skill 28, block 17
Advantages: Cheap. Effective against lightly armored infantry or drones. Disadvantages: -2 to block sabots and other solid shot, -1 to block cannon shells and other high-velocity projectiles (doesn't stack with -2 for sabot), doubles range penalties, only blocks one extra rapid fire hit per 2 MoS.
15mm splat gun 'Flechette pod': skill 29, block 17
Advantages: Very cheap. Works against all projectile types even at close range. Light enough to be shoulder-mounted on power armor. Halve range penalties. Disadvantages: -2 to block sabots and other solid shot, -4 to block SEFOP, one-use only (cannot be reloaded from internal magazines; entire barrel must be replaced), inefficient and marginally effective against any targets besides incoming projectiles or unarmored civilians.
25mm payload rifle 'Interceptor gun': skill 26, block 16
Advantages: Cheap, high ammo capacity, can load non-lethal and utility munitions (tangler, jammer, flare, etc.). Disadvantages: -1 to block sabots and other solid shot, doubles range penalties and penalties from feints, only blocks 1 extra rapid fire hit per 2 MoS to a maximum of 3.

Unlike ranged attacks, the range penalties for point-defense block rolls are INVERSE to the distance (speed is already factored in to the shot type penalties). To represent the need to track the threat quickly, the maximum range at which these can target a projectile is 1/2 their normal short range. The baseline distance to attempt to block a projectile with no range penalty is 5 miles (only possible for an area defense laser). Invert the progression so intercepting the shot gets harder as it originates from closer, to a maximum of -18 at 10 yards (closer than this is simply not possible). Although it might seem absurd that it's technically possible for a laser to block a 100mm cannon shell fired from 10 yards away (with a roll of 4 or less on 3d6), this 'block' roll also accounts for the weapon's ability to auto-target and disrupt the firing weapon's sensors at very close range. To get the range penalty, turn the listed penalty for a given range into a positive, and then subtract 22.

Although the blocking mechanic is mostly using a static number depending on how good the tech of a particular vehicle is, the commander can adjust and tune its defenses, while a gunner can do the same with their own ordnance to try and slip through point defenses. As a result, several technical skills and 'Tactics' can be used to make 'feint' and 'beat' attempts. 'Feint' usually uses Tactics but might also use technical skills (opposed by the enemy commander's own skill). A 'beat' instead uses gunnery skill and involves rapid un-aimed shots in an attempt to force an opening in the enemy's point defenses, opposed by the commander's Tactics. Aside from this, the main way to get through an enemy's defenses is by outflanking them: Any given point-defense system is considered a "shield" that only gives full coverage against the front 90 degrees, with the usual flanking penalties for attacks from the side, and unable to defend at all against attacks from the rear.

Then there is the 'Parry', which represents jamming, spoofing, blinding enemy sensors, and other electronic warfare. Unlike blocking, which is based on the skill of the computer program controlling the turrets and the weapon's accuracy, parrying is based on the driver or commander's electronic warfare skill, with the quality of the systems providing a DB (or penalty, if they're cheap or obsolete). Parrying more than one attack in a turn gives penalties as per usual, and if the enemy has a sensor lock with more than one type of sensor system, it has a -2 penalty for each sensor system beyond the first locked onto them. Normally, jamming systems either provide no bonus, or (if they aren't good quality) a penalty. Decoys and chaff, meanwhile, give a defense bonus but have limited uses (generally between 5 and 10).

Dodging works mostly as written but also incorporates stealth. If the enemy doesn't have a sensor lock, a defending vehicle gets a +2 bonus to dodge attempts. If they have more than 1 type of sensor locked on, there's a -2 penalty for each beyond the first. Since vehicles in this setting often have excellent handling (in exchange for worse stability) compared to 21st century AFVs, dodging is a very viable and important defense.

(Note that energy weapons such as microwave beams and lasers can never be blocked, obviously, but they CAN be dodged or parried, but parrying energy weapons suffers a -4 penalty unless the vehicle is equipped with specialized anti-laser smoke launchers. Lasers aren't powerful enough to penetrate most AFVs even on their sides or rear, but they're devastating against infantry, including power-armored infantry, drones, and other light targets, and can snipe the point-defense turrets, heat radiators, sensor turrets, and other weak points on AFVs. Most are 'sealed' and can't be disabled completely by a microwave attack, but if they fail an HT roll against it, the disruptor affects their sensors and computer-controlled turrets).

Furthermore, it's possible for multiple defenses against the same attack. Normally the driver/pilot will make the dodge roll, while the commander (or gunner, if they share roles) will make the parry roll, and the block roll is automatic. That means vehicles will get THREE attempts to defend against most incoming attacks. Since any projectile that gets through will usually deal severe damage if not incapacitate the target outright, this is by design; for an RPG it's important for fights that aren't a one-sided ambush to last long enough for the combatants to volley insults and threats at each other, scream at their allies over the radio that they need support, and so on. Since the fighting will mostly be in urban areas this means that AFVs dueling each other will often cause HIDEOUS amounts of collateral damage to the surrounding area. Since the setting is a bleak, cyberpunk corporatocratic hellhole controlled by a corrupt and uncaring government, the paramilitary forces involved (especially PMCs with good lawyers and terrorist groups, but even including most law enforcement) are usually pretty cavalier about property damage and bystanders getting hurt or killed, so heroic (or anti-heroic) commanders who go out of their way and take additional risks to minimize harm to cities and civilians are the exception, and can use more creative methods (herding the enemy into a corner and making them surrender, luring them into hidden obstacles or deployed traps, sneaking past without contact, or even getting in close and ramming enemies to flip them over or crash them into a wall) instead of cutting loose with missiles and shells.

In general, to resolve combat, I think the "Chase combat" rules from GURPS Action 2 would work well, although with range bands multiplied by 10, since most often one side or the other will be trying to get away. You might be asking how it's possible for criminals or terrorists driving a damn TANK around to escape pursuit, but that's part of the setting; all kinds of networks are extremely vulnerable to hacking due to the advent of quantum computers, and the average citizen is far less cooperative with "the legitimate authorities" than they would've been in a 2020s first world country.

[The_Ryujin]

Just a warning, the projectile weapons in Ultra-Tech are kinda jank with magazines weights don't make sense and generally weak stats compared to the TL 8 weapons in High-Tech. This one part early installment weirdness and one part executive meddling (there was a very vocal minority whining about preceived over complexity in GURPS and this being the early era of mass internet, the higher ups mistook it as legitimate complaints and order a total rewrite of the book which... muddled things).


For example the 25mm "assault cannon" is actually an janky Ultra-Tech version of the real world canceled XM307 which is actually an automatic 25mm grenade launcher. Despite this the rounds it uses weigh as much as a full sized 25mm cannon round (and it's magazine is actually a TARDIS! It weights only 12lbs despite holding 35lbs worth of ammo!). The round should actually weigh only 0.3lbs, which better lines up with the 12lbs magazine.

An actual TL 9 25mm autocannon would be more like:
Damage Acc Range Ewt. ROF Shots ST Bulk Rcl Cost LC
6d×4 p++ 6 2,100/8,800 244/ver 10 ver. 28M -11 2 $55,000 1

As for an active defensive system, I have a ADS write up in the works but that's a few posts down my rather slow pipe line.

[Rupert]

The 25mm 'Payload Rifle' is more likely based on the 2cm 'Light Assault Gun' from Traveller as much as the failed US OICW program. As a man-portable support weapon it should not have a round as powerful as a full 25mm auto-cannon round - it would then be unusable by non-powered troops. Its name tell you what it's intended use is - firing shells that rely on their payloads for effectiveness, and not their kinetic energy.

The 25mm 'assault cannon' fires the same ammo as the above payload rifle, and is thus clearly not intended for the same role as a modern 20-25mm auto-cannon - it's more like a modern 30-40mm automatic grenade launcher (like the AGS-17 or Mark 19). The ammo weight is definitely wrong, though, and looking at the 25mm payload rifle and the listed weight for a single shot of 25mmCL it should be something like 42 pounds. The light auto-cannon/heavy machinegun role is filled by the 15mmCL Heavy Chaingun (especially ETC versions). The payloads should probably be bigger and more effective than they are, though (aside from the shaped charges which are bore diameter dependent more than mass dependent).

The accuracy of many of the slug throwers is probably lower than it should be, but otherwise they are reasonable weapons, and remember that binary and ETC versions are an option and ETC versions firing ultra-tech ammunition are truly scary weapons.

[The_Ryujin]

Originally Posted by Rupert

The 25mm 'Payload Rifle' is more likely based on the 2cm 'Light Assault Gun' from Traveller as much as the failed US OICW program. As a man-portable support weapon it should not have a round as powerful as a full 25mm auto-cannon round - it would then be unusable by non-powered troops. Its name tell you what it's intended use is - firing shells that rely on their payloads for effectiveness, and not their kinetic energy.

The 25mm 'assault cannon' fires the same ammo as the above payload rifle, and is thus clearly not intended for the same role as a modern 20-25mm auto-cannon - it's more like a modern 30-40mm automatic grenade launcher (like the AGS-17 or Mark 19). The ammo weight is definitely wrong, though, and looking at the 25mm payload rifle and the listed weight for a single shot of 25mmCL it should be something like 42 pounds. The light auto-cannon/heavy machinegun role is filled by the 15mmCL Heavy Chaingun (especially ETC versions). The payloads should probably be bigger and more effective than they are, though (aside from the shaped charges which are bore diameter dependent more than mass dependent).

The accuracy of many of the slug throwers is probably lower than it should be, but otherwise they are reasonable weapons, and remember that binary and ETC versions are an option and ETC versions firing ultra-tech ammunition are truly scary weapons.

The Payload Rifle is the Barrett XM109 Payload rifle, it even looks like how it's described in the Ultra-Tech. It also fires the same grenade round as the XM307, which is a more powerful round then the one used by the XM25 "Punisher" (which is what the standard 25mm grenade round in the book is based on, note that the OICW fired a 20mm round though it did inspire the 25mm follow up).

As for how it's used, yeah. That's kinda what I was talking about heh. The reason I brought using the assault cannon as an example of odd stats since it was a weapon system the OP was talking about using so I though I'd warn him of some of the issues with it. That and I got the vibe he was using it more like a an actual cannon then a support weapon. But yeah, it's a grenade firing machine gun and should be used to bring chem payloads to target rather then KE.

Also yeah, ETC is scary, by a bit too much actually. If the gun design system ever see's the light of day they're getting dropped to only a 1.25 × boost which is closer to current real world exceptions of the technology. 1.5 × is crazy good.

[FrackingBiscuit]

Pyramid #3/37 has stats for TL9 25mm and 40mm autocannons, among many others ranging from civilian hunting rifles to 160mm howitzers and 400mm cruise missiles. Might also be interested in the 64mm dual-purpose gun, which sounds similar to the 60mm gun you described.

Should note that the 25mmCLR used in the autocannon is supposed to weigh 1.25lbs according to the ammo table, but the magazine apparently uses the same TARDIS tech as the payload rifle (1.25lbs per round, 100 rounds weigh 125 lbs, loaded 100-round magazine weighs... 120lbs?). Though as others have pointed out, the payload rifle's 25mm grenade should weigh something like 0.3lb, while 1lb is about right for a 25mm cannon round. 25mm caseless rounds are some kind of cursed.

Actually, looking at the 40mm cannon, a 125-round magazine weighs 350lbs, but one round weighs 4lbs...

...well, the other weapons all seem to be fine at least.

[The_Ryujin]

@FrackingBiscuit Yeah, I know about that Pyramid article and it was nice to get some more gun options but like you said, they carry some odd baggage.

A revamp of Ultra-Tech's guns are also in the pipeline to bring them into line with High-Tech and to add some more common guns types to the list. Not all the guns are totally bad but things like overall weight and magazines need adjusting (the magazines in Ultra-Tech usually out weight their TL 8 counterparts and that's.... odd). Oh and costs for the magazines would be nice too heh.

If the OP ever stops back in, I'd be glad to help flesh things out with him and try to come up with some "patch updates" (which will also help me out in the long run as well heh).

[Fred Brackin]

There was a brief push after the 20mm OICW concept was scuttled to revamp it as a 25mm. This was based on the idea that fragmentation from 25mm autocannon rouds was "adequate". Perhaps someone noticed that high velocity autocannon rounds had much heavier jackets than low velocity launcher grenades. When you're turning your jacket into your fragments ths sort of thing matters.

The very late 3e minibook Modern Firepower is relevant to what went into the very early 4e Ultra-Tech. I believe there were stats for the OICW in MF. Aso look at Transhuman Space and the 3e UT2 which was heavy in guns as viewed in the late 90s.

[The_Ryujin]

Originally Posted by Fred Brackin

There was a brief push after the 20mm OICW concept was scuttled to revamp it as a 25mm. This was based on the idea that fragmentation from 25mm autocannon rouds was "adequate". Perhaps someone noticed that high velocity autocannon rounds had much heavier jackets than low velocity launcher grenades. When you're turning your jacket into your fragments ths sort of thing matters.

The very late 3e minibook Modern Firepower is relevant to what went into the very early 4e Ultra-Tech. I believe there were stats for the OICW in MF. Aso look at Transhuman Space and the 3e UT2 which was heavy in guns as viewed in the late 90s.

There is also stats for it in High-Tech and a sorta version of an TL 9 follow up that is in the Basic Set called the ICW that has a 6.8mm rifle built around a 25mm grenade launcher.

Modern Firepower is a great book, kinda wish High-Tech kept some of the ideas in it (I don't see why a AD of 1.25 is hard, not like you're not using a calculator anyways). And of course, Transhuman Space being inspired by gems like this lol Yes, those are the origins of the 15mm gryoc. Ultra-Tech 4th ed is also guilty of this, metal storm's imprint was all over it heh (I kinda saw that concept dying hard from day one).

[Fred Brackin]

Originally Posted by The_Ryujin

And of course, Transhuman Space being inspired by gems like this lol Yes, those are the origins of the 15mm gryoc..

Nope, that (probably a concept photo from the Army's "Future Warrior" program) was the origin of Transhuman Space's "15mm micro-missile" and its' "arm pods". Transhuman Space didn't call them "gyrocs".

The origin of the Gurps "Gyroc" was probably the very first Gurps Ultratech which was a very early 3e book (and largely repeated in Gurps Cyberpunk). There the Gyroc derived from the Real World "Gyrojet" of the 1960s and probably some weapons from the Stainless Steel Rat series of books.

All of that was well before that series of Army press releases.