[High-Tech] Questions about Sidewinders

[Michael Thayne]

I have a number of questions about the Sidewinder missile from High-Tech:

1. How do they work, game-mechanically?
2. Given the answer to (1), whatever that is, how realistic and game-balanced are they?
3. How can you extrapolate their performance to other ABF warheads, real or sci-fi?

What's confusing about the Sidewinder, game-mechanically is that it's one of only two ABF warheads in all of GURPS 4e (the other being a round for the Saco MK 19 MOD 3). It's also one of only three multiple-projectile that's a self-propelled projectile rather than a gun. The latter means no 1/2D, which I think means the rules for "extremely close range" are just ignored—using those rules here would be pretty crazy!

Okay, so we need to make a rapid-fire attack. That's +7 for 194 shots. Does the -4 for attacking from 10 yards away apply, or is that just fluff? What about the +4 for airburst? Obviously it's an airburst weapon by the real-world definition, but is it an airburst for GURPS game mechanics? The airburst mechanics seem to strongly assume an explosion with fragmentation damage—an important part of the mechanics is that airburst rounds "inflict only fragmentation damage", which the standard ABF Sidewinder doesn't do.

Let's assume that either the range penalty and airburst bonus both apply, or they both don't. And let's assume the target is an SM +5 aircraft moving at a little under 700 yards/second (-9 speed penalty). If those assumptions are correct, a "locked on" Sidewinder will roll against skill-17 to hit, and average six or seven hits. That seems pretty reasonable for killing aircraft with around 100 HP, DR 3, and Unliving (60ish damage).

However, depending on the mechanics, we could actually be talking about two or three hits on average (20-odd damage) or ten to eleven hits on average (around a hundred damage).

How does this compare to the Vympel R-3S? In airburst mode, you only have fragmentation damage to deal with, and it will average just shy of 30 damage on average. An oddity of the fragmentation rules mean it's arguably better to miss by one, at least if you're not getting the explosion damage—but if you houserule that direct hits still attack with skill-15 for fragments, you just get a minimum of one hit on a 16-18, then we're getting an average of two hits, for just slightly less damage on average than a hit with the ABF warhead.

So on the "no range penalty/airburst bonus" interpretation and the "bonus and penalty cancel" interpretation, the ABF warhead has a slight edge over the HE-AB warhead, which I suspect is realistic (and possibly meaning the weird rules should be marked as very optional). On the other hand, if the ABF gets the airburst bonus with no range penalty, then it's doing around 70% more damage, a massive improvement—is that realistic?

If you do want to futz with the rules for ABF for weapons other than the Sidewinder, using an RoF multiplier anywhere from 100 to 199, with piercing damage equal to the equivalent HE warhead's fragmentation damage, is probably fair. If you have the damage for a solid projectile, you can also use the "divide damage by sqrt(RoF)" rule from High-Tech.

Thoughts? Mistakes in my reasoning? Should I interpret the rules ambiguity to be maximally favorable to ABF?

[Refplace]

There is a minimum range which was built in for safety reasons.
I cant say the distance but it wont arm the warhead until it has traveled a short distance.