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Rcl and ST in GURPS

Idle conversation on the Discord chat about a full-auto .50 BMG rifle (as opposed to a machinegun) led to the comment that for sufficiently strong and large races or creatures, they really should be kitted out with battle rifles in sufficiently impressive calibers.

I mean, why wouldn’t a large-enough race make a rifle capable of firing 14.5mm KPV rounds?

Now, it’s been a while, but I don’t think a character’s ST has any impact on a weapon’s stat line.

Let’s look into fixing that.

Options

Really, we’ve got three options.

Acc is a bad choice. It can be shown, and I always treat it, as being inherent to the weapon, with 22 + 2*Acc giving a good measure of the bench-rest precision of the weapon.

Rcl is a measure of how many hits you get on a single roll when a weapon is used in rapid fire. That sounds rather promising.

ST is how strong you have to be to employ the weapon normally; being lower than the ST provides a skill penalty.

Of these, Rcl seems the obvious bit – a sufficiently large and strong (mostly strong) shooter should be able to lower the Rcl down from very high levels to a minimum of Rcl 2 as a good guideline (Rcl 1 being the signature of recoilless weapons – “or nearly so,” and so are best avoided both for metagame and consistency reasons).

Mechanics

So, for every boost of ST over its listed value, you can hold it steadier.

Let’s “use what’s there,” which means natural breakpoints should be considered at 1.5x ST, 2x ST, and 3x ST. Continuing this for each multiple of ST seems OK. So let’s say -1 Rcl for 1.5xST, then another -1 at 2xST, and then another -1 for each multiple thereafter.

Sanity Check

Popping over to the GURPS Basic Set, we have some generic guns. What would those look like?

The lowest handgun is ST 8, and Rcl ranges from 2-4. The highest ST requirement is ST 12.

Rcl management doesn’t matter for Rcl 2 weapons. But a snub revolver has ST 8 and Rcl 3, so it would be Rcl 2 at ST 12 using the 1.5x guideline. A .45 ACP auto pistol is Rcl 3 and ST 10, so ST 15 would give you Rcl 2. The .44M auto-pistol would need ST 18 to operate at Rcl 3, and ST 24 for Rcl 2.

If we ignore the 1.5x breakpoint and just say “multiples of ST,” then our handgun selection requires ST 16 for the snub revolver for Rcl 2, the .45 ACP is ST 20 for Rcl 2, and the .44M would need ST 24 for Rcl 3 and ST 36 for Rcl 2.

Push into the rifles for the Big Dogs. A .308 Battle Rifle is ST 11 and Rcl 3; so we’ll choose between ST 17 and ST 22 for that first and only -1. For the single Rcl 4 example, the .338 also has ST 11B (ST 8 with the bipod). Firing the beastly .338 as an effective semi-auto should be hard. Rcl 2 would either require 3x or 4x ST; that’d be ST 33 or ST 44 from the offhand position, and ST 24 and ST 32 from a bipod.

For the Big Dogs, such as the .50 AE Desert Eagle (ST 12, Rcl 4) and the .454 Casull (ST 12, Rcl 5) you will need ST 24 or 36 to shoot them if we allow a Rcl break at 1.5xST. Basically the first is barely doable if you’re a “can squat 650 and bench 450” kinda guy, but everyone else suffers. For the Rcl 5 Casull, a real human is simply not capable of being strong enough to do this, and that’s with the first break at 1.5xST. If you decide that only multiples of ST will do, it’s impossible for both.

Shotguns firing slugs are mostly in the Rcl 3-5 range and ST is 10 or 11; you’ll still want to be ST 15-16+ to claim any sort of bonus. Rcl 2 with a Nitro Express (Rcl 7) would require a Basic Lift pushing half a ton (ST 70).

More importantly, a full-auto Barrett M82A1 with ST 13 and Rcl of only 3 could be fired at Rcl 2 with ST 20.

This doesn’t seem crazy-town.

Parting Shot

Not sure I’d go do this. I’d especially not do it without checking with Hans and David for the assumptions behind Rcl and ST that are built into the existing weapon tables. For a heavy and strong enough mount, such as mounting six 12.7x99mm machineguns on an F86 (5-8 ton empty to max weight), this might effectively be ST 75 or so and yeah, bring down six full-auto M2s to Rcl 2 each. A scalable quantity like this would be fun for mounting, again, the ST 21 M2HB on a lightweight vehicle, or seeing just how strong a Terminator would have to be to hip-fire a M134 7.62mm gatling gun. At some point, a character will be heavy and strong enough to effectively be considered a mount for a weapon  (if this seems implausible, picture a full-auto airsoft rifle, which has effectively no recoil to speak of) and bring it down to Rcl 2, the same way the 20mm M61 gatling gun is Rcl 2 when in its mount.

 

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2 Comments

  1. I’ve used Trained ST for this purpose, with Guns skill having a Fast progression when it comes to Trained ST bonus for meeting MinST for firearms.

    I reduce Rcl at x2 ST, x3 ST, 4x ST, etc. I’ll also give ad hoc bonuses or minuses to certain guns, with heavy weapons (so decent MinST) firing anemic rounds, like the American 180, actually having a lower effective ST rating for this purpose.

    I’ve considered having x1.5 ST reduce Rcl, which would make this matter more for human-scale shooters, but haven’t done it yet.

    I actually do reduce it down from Rcl 2, down to Rcl 1.5 and Rcl 1, with the justification that if a recoil-managment system like that for the Kriss Vector can get Rcl down to an effective 1, so should being big and strong enough in comparison with the weapon. And, yes, the analogy I mentally used was lasers, water sprayers, soft air, paintballs and suchlike. Rcl 1 isn’t magical, it just means more hits on autofire and if the recoil is miniscule in comparison to the shooter, I think it qualifies. Mind you, normal humans usually don’t achieve it with anything but *maybe* full-auto .22 LR weapons.

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