Sorry that I missed GURPS-Day yesterday. I was travelling in Germany for business. That was my first time in Europe since 1998 or so, when I spent three weeks near Eindhoven in the Netherlands. I need to go back.
Come to think of, there seems to be a litmus test for whether a given RoF system produces good results. I’m probably missing something, but here are some points that I noticed:
- For a Rcl 1 weapon (e.g. laser pointer), it should be possible to achieve 100% hit rates with reasonable skill, even when not engaging Close Stationary Targets (B408).
- For a Rcl 1 weapon with a very high RoF, doubling RoF should roughly double the number of hits, and shouldn’t increase the bonus to hit. A very high RoF in this case refers to such RoFs that in a single pass that intersects the target, there is no possibility of the pass occurring between the shots, given the weapon-training speed of the shooter (i.e. when a successful pass always indicates at least one hit).
- Firing 600 shots over a 1-minute turn should produce the same percentage of hits as firing 200 shots over a 20-second turn or as firing 10 shots over one second (unless there’s an Aim involved that only affects some of the shots), regardless of Rcl (unless Rcl is so bad that a penalty accumulates, which, in 4e, it doesn’t, ever).
- Shooting a target farther away (extra -5 for range) should produce the same results as shooting a smaller target (-5 SM), and the same as shooting a smaller target on a larger target (-5 SM smaller target on larger).
- A Homing weapon should produce roughly the same percentage of hits regardless of RoF, before things like warhead fratricide are taken into account.
I think a lot of these points are an outgrowth of the “people on infinite featureless field of battle” mentality.
Let’s take the first. With a laser weapon or something else with Rcl 1, you should get a lot more hits, right? In combat?
No. Not just no, but hell no. For my Dodge This article, +Peter V. Dell’Orto and I looked up the hit rate of – wait for it – people playing games like Photon or Lazer Tag. These are Rcl 1 weapons with RoF 1, usually. No autofire. But the hit rates tended to be about 6%. If you’re hitting that few times with semi-auto fire, you’re right in the center of the GURPS autofire principle: it’s for getting a few hits from many shots, not a lot of hits. Granted, this situation is chaotic, people aren’t aiming much, it’s usually dark. Hey, much like combat is supposed to be.
So point-the-first is dubious. Go ahead and try it. I bet that if you attach a laser sight to an airsoft rifle and could somehow calculate the percentage of time your beam was on-target in an actual chaotic situation, like an airsoft or laser tag game, it would be quite low. Your usage mode would also likely be “sweep the beam across the target,” not “hold the beam on target for a high percentage of the time.”
The second point – very high RoF where you can’t pass between the shots – is a misapplication of the rules. If you’re all or nothing, you handle this not with Rcl 1 and high RoF, but with RoF 1 and higher damage. This is a single-shot weapon for all intents and purposes. Rcl 1 is used for zero-recoil weapons like lasers, true, but it’s also used for firing three rounds from a shotgun loaded with shot rather than slugs. Rcl 1 is the lowest Rcl level, true – but it’s probably best read as “minimal spread,” but not single shots.
The third point totally neglects that a target can – and likely will – move. Hell, the shooter might move! Rules that achieve less, more, or the same hits as time increases can all be argued to make sense. Fewer hits because of much more opportunity to have relative chaos between shooter and target. More because of more time to compensate for that motion. The same due to a thought-to-be constant probability of hitting in aggregate taking all the shots as independent events. If you have an ability to put 76% of shots on target, that should be 76% over one second or one hundred. So this one assumes something that needn’t be true, but could be.
The fifth point is probably correct if you’re talking about cones of fire, and is probably a good design goal.
I’ll neglect the 6th because Homing is a game-mechanical term, and the precise thing its supposed to be modeling is left vague, probably intentionally.
+Mark Langsdorf took a stab an an alternate way to look at Rapid Fire over on his own blog. As discussed in the forum thread above (and it’s worth reading, mostly) it’s not bad. Since Size Modifer and Range are both based on the Size and Speed/Range table, having the Rcl/RoF mechanic tied to that table makes good sense.
I’ll return to this a few times in the upcoming days. There’s a scatter diagram I did a while ago that’s worth revisiting for fun, and I want to try and tie autofire rules to the area fire rules as well.