Equipment Locker: Gyroladar Launch Pistol

A friend and I regularly pick each others' brains for GURPS concepts, ideas and advice and one of our recent discussions was a kind of "enchanted weapon" for a boss to wield in a semi-hard TL10 space opera game where humanity fell then rose again (somewhat like Traveller). The idea of "boss loot" is tricky to do in science fiction, since the vast majority of objects are mass-produced (or 3D printed) but fall-and-rise-again space opera gives you a certain amount of wiggling room if the previous civilisation was more advanced than the current one. The other constraint was that it can't rely on special ammo, since the specialness of the weapon degrades a bit if you can just stuff it's ancient 10mm rounds into your modern gun.

The idea I came up with was a gyroc pistol with an active targeting sensor on it, that uses it to auto-adjust itself. I didn't get time to build it in detail at the time (since anyone who regularly reads this blog should know I'm fond of using the combination gadgets rule to make new items) but I took some time to do it properly, so here's the entire process, as well as the result.


In game mechanic terms, the benefit active sensors give to weapons is exact knowledge of distance and speed, which gives a +3 bonus to aimed shots if the target is being tracked. The benefit of an active sensor as opposed to a simple scope is immediacy – a scope that provides +3 to accuracy requires you to Aim for 3 seconds to get the bonus. An active sensor provides the +3 after a single Aim manoeuvre, which also aims the weapon itself.

The Build
The first basic component is the weapon itself. Here we've only got two choices: the gyroc launch pistol or the gyroc pistol (Ultra-Tech pp. 144-145). The second is actually a revolver, with a four-round chamber as opposed to a magazine, so the launch pistol is probably better.

Now we need our sensor. We need something that can lock onto a target to provide precise speed and range information. Radar seems most natural but is mostly designed for target acquisition, not tracking, and often has difficulty detecting ground-based targets. Since this is an anti-personnel weapon, that works against us. The next most obvious is ladar (p. 64), which is intended to track already-acquired targets and explicitly provides the +3 bonus to aimed shots for an active sensor lock. Since you can't really shoot something you can't see, this is fine. The one possible caveat is that ladar range can be reduced to 10% in heavy rain or snow but this turns out to be a nonissue – the small ladar's range is 10 miles so the worst possible range is one mile (1,750 yards). The gyroc launch pistol's range is 1,900 yards. Close enough. The small ladar unit is $2,000 and 1 lb.

Now we need a computer and a piece of software to interface between the ladar and the gun. The Special Modes entry for active sensors (p. 63) states we need targeting software to utilise this ability. The entry for this software seems to indicate that it's for a HUDlink instead... and gives two Complexity ratings for different bonuses. We'll have to put this down to poor editing and pick the lower of the two since the ladar will be doing most of the work. This software is Complexity 3 and five times normal cost: $500 at TL9. We also need a computer to run it on. The tiny computer (p. 22) is more than sufficient. That's another $50 and 0.05 lbs

Now here's where it gets a little fudgy. My intention here is to have a gyroscopic system analogous to a reaction wheel inside the weapon, which makes micro-corrections to the direction the gun is pointing based on the information from the ladar to increase accuracy. There's nothing that can do this RAW in Ultra-Tech, so we have to go off the track a little. The gyrostabilised weapon harness (p. 150) is the closest in the books. This compensates for the instability of a person running at full speed, so I think a smaller amount of this might work. Adding this directly into the gun is a problem however, since it weighs a pound per pound it affects – we need to add an extra pound of gyro per pound of gyro... which would quickly give us an infinite-weight gun. I think a single pound-worth of this is sufficient to give a little kick in the right direction. So that's $200 and 1 lb. 

Now we simply use the Combination Gadgets rules (Ultra-Tech p. 16) to combine them. There's one special consideration here: the gyroc pistol weighs a total of 2.0 lbs, but 0.7 lbs of that is the magazine and ammunition, which doesn't qualify for the weight reduction. In this case, the gun is the heaviest component, so this isn't too much of a problem. Our total weight is:

1.3 + 0.8×(1.0+1.0+0.05) + 0.7= 3.64 lbs

Which we'll round up to 3.65 lbs to make the number nice. As for cost, we do the same thing but this time the ladar is the most expensive. The software doesn't get the cost reduction since the saving is from shared casing.

2,000 + 0.8×(300+200+50) + 500 = $2,940

Which we can round up to $2,950, or even $3,000 if you prefer nice round numbers. Legality class for combined gadgets is the lowest of the components, which is the LC2 targeting software, so the gun is LC2.

Most of the work is done but there's one final consideration we need to make. Adding all this high-tech gear has increased the weight and size of the weapon. We need to figure out whether the ST requirement or Bulk has changed.

I'm not aware of any concrete rules for calculating ST requirement for guns (though there are for beam weapons) so we should compare to pistols of a similar weight. Comparing to the ST 11 magnum pistol (p. 137), our gyroc is a little heavier so we'll increase it to ST 11. For Bulk, we can use the formula in Eidetic Memory: Blaster and Laser Design from Pyramid #3/37: Tech and Toys II, which tells us that Bulk very narrowly doesn't change.

The Result
Below are the full stats of the weapon, including a TL10 version which is slightly cheaper due to the reduction in software cost by TL. The accuracy may not seem particularly high, which was the initial goal, but keep in mind that Acc 4 is typically reserved for rifles rather than pistols. Also remember that pistols allow you to automatically claim another +1 for bracing. This pistol effectively has Acc 5. That's pretty damn good.

If you want to make it a true artefact, slap on some Styling in the form of gilding (+19 CF), engraved scripture (+1.5 CF), enamelled depictions of deities (+2 CF), or anything else from Decorative
Embellishments (Dungeon Fantasy 8 – Treasure Tables, pp. 53-55).

TL	Weapon	Damage	Acc	Range	Weight	RoF	Shots	ST	Bulk	Rcl	Cost	LC
9 10	Gyroladar Launch Pistol Gyroladar Launch Pistol	6d pi++ 6d pi++	4 4	1,900 1,900	3.65/0.7 3.65/0.7	3 3	6(3) 6(3)	11 11	-2 -2	1 1	$2,950 $2,600	2 2