Handling Long-Range Musketry

[Varyon]

This is a spin-off from the What kinds of firearms would people start making [After the End]? thread, wherein there was some debate over how accurate smoothbore muzzleloaders should be, with a nod toward their strange exterior ballistics (namely, that they have a bad habit of deviating from their aimpoint more rapidly than standard GURPS Range rules suggest - this is due to a combination of factors, from not being a perfectly-smooth sphere to changes in trajectory due to spin).

Based on the numbers from a Master's thesis linked in that thread, I think I have an idea of how to handle this in GURPS. In that, at some point between 50 yards (-8 to hit) and 80 yards (-10 to hit), the projectiles picked up somewhere between -3 and +2 to skill, with an average of -0.111 (I approximated this using 1d-4). Beyond this, there was something like a further -1 to hit at each -1 from Range, for a total of -2 per point of Range. The shots only went out to about 170 yards, however.

Still, from this, a bit of a pattern emerges. A low resolution solution is to double all Range penalties beyond 70 yards, so that a musket sees range penalties as (...-7, -8, -9, -11, -13, -15, -17...). A bit higher resolution option would be to replace the first -1 with 1d-4, and you could possibly push the range back a step, with (1d/2)-2 beyond 50 yards, rounding normally (so you'd be between -1 and +1 to hit). A much higher resolution option would be to do something like (1d/2)-2, 1d-4, 1d-5, 1d-6, 2d-10, 2d-11, 2d-12, 3d-16, and so forth (although I'd replace each nd with 1dxn, so that you don't get a tighter spread with each added die).

The range at which this starts to come into play is going to vary. The above is perhaps appropriate for an Acc 2 weapon (not certain how good the weapon used in the testing was). Each +1 to Acc from being Fine (Accurate), opting for Careful Loading, and so forth, is +1 SSR to the range beyond which the above effect comes into play. Higher-quality ammunition may also be available - while typically below GURPS resolution, such ammunition is double cost but is +2 SSR to the above range (and this does stack with Accuracy modifiers). Each -1 to Acc from being Cheap, black powder fouling, and so forth, is -1 SSR to the above range. Using field-expedient projectiles drops the range due to Acc penalties and gives a further -2 SSR to the range.

Do keep in mind that, with the sorts of penalties the character is already going to be suffering for Range (by default, the above rules kick in at 100 yards, or 70 if using (1d/2)-2, which correspond to penalties of -10 and -9, respectively; a base Acc 1 pistol firing field-expedient projectiles is about the worst situation possible, and even it doesn't see an effect until it's at -7 or -6 from Range), the above typically isn't going to make much difference, and can probably be safely ignored in most campaigns. If a musketeer sniper harms your Sense of Disbelief, however, the above is a way to handle that. If using Tactical Shooting, note that the above modifiers come into play after the MoA-based skill cap.

[swordtart]

I was looking at HT and was surprised to see that the Brown Bess is ACC 2, whilst the Baker rifle is only 1 better at ACC 3. Given the fact that the Baker was the sniping weapon of it's era this seems a bit poor.

I presume all the listed ACC mods are in some supplement that I don't have. Can you cite the books they appear in so I can hunt them down.

I did refresh my memory of ranged combat and it was is somewhat different to how I remember it. The I realised I was still thinking in terms of 3rd edition.

It seems to me you could hand wave all this away by simply lowering the base ACC for smoothbores. The indication is that they were not aimed (very few munition weapons have any sort of sight) but simply pointed. What if we are looking at this the wrong way. Not that they were inaccurate because they were not aimed, but that because they were inaccurate aiming provided no advantage.

There were exceptions and some guns had tube sights etc. but these could be the FINE guns you mention. By carefully controlling the powder, selecting a good ball and loading carefully to avoid distorting it you could achieve fair results.

ACC 2 allows you to shoot at +4 after two seconds aiming. Do those ACC modifying rules allow you to exceed the normal 2x base ACC rule? If not you would be better just aiming a bit (and 2 seconds isn't that long if you can only fire every half minute or so).

If you lower the ACC of the musket to 1, you can at most add another 1. ACC 2 makes hits at 50 and 100 yards hard, but not impossible, but it quickly shifts the 150+ range shots into the miraculous.

I also note in the 3rd edition Wild West that shotguns had a maximum range of 150 yards. That would be another way to handle it. Unfortunately in the same book the Indian musket has a range of almost a mile and a half. How? By using it like a howitzer?. I don't think these wacky numbers are confined to 3rd edition products.

[Varyon]

Originally Posted by swordtart

I presume all the listed ACC mods are in some supplement that I don't have. Can you cite the books they appear in so I can hunt them down.

Fine (Accurate)* is found in both High Tech (p79) and Low Tech (p95-96). Careful Loading is similarly found in both books (p86 and p95, respectively). Cheap apparently isn't actually an option for firearms - oops. Black powder fouling is also found in the above books (p86 and p95, respectively). Field expedient projectiles are, yet again, found in both books (p163 and p95, respectively). Finally, the Acc-based cap to final effective skill is from Tactical Shooting (p32). The higher-quality musket balls aren't in any GURPS books and represent balls that are better fits to the musket and are more perfectly spherical. In addition to extending the range before the ball starts deviating from its flight path, such might also serve to give a +2 to the skill cap from Tactical Shooting.

*I erroneously had this as Reliable above; it's been changed, now.

Originally Posted by swordtart

It seems to me you could hand wave all this away by simply lowering the base ACC for smoothbores. The indication is that they were not aimed (very few munition weapons have any sort of sight) but simply pointed. What if we are looking at this the wrong way. Not that they were inaccurate because they were not aimed, but that because they were inaccurate aiming provided no advantage.

I don't know how far back it goes, but GURPS Acc actually has a close relationship to the weapon's MoA - you can see this in Tactical Shooting, where Acc serves to allow you to calculate maximum effective skill (which is a function of MoA). It's likely the tested muskets actually do have MoA consistent with an Acc 2 weapon.
I'll also mention something that someone else brought up in the other thread - one good reason not to train your soldiers to aim in formation fighting is that if they opt to Aim, they're likely to do so at the target(s) that stand out the most, which will mean many of your soldiers will be aiming at the same guy, which prevents you from properly spreading out the destruction (better to hit 3 guys with 1 bullet each than 1 guy with 3 bullets...).

Originally Posted by swordtart

ACC 2 allows you to shoot at +4 after two seconds aiming. Do those ACC modifying rules allow you to exceed the normal 2x base ACC rule? If not you would be better just aiming a bit (and 2 seconds isn't that long if you can only fire every half minute or so).

First, it's +Acc the first second, then +1 for each of the next two seconds, so it's actually 3 seconds of aiming to get that +4 (you can get another +1 by bracing, and a final +1 by making an All Out Attack, of course). Having a Fine (Accurate) weapon, or using Careful Loading (or the more modern equivalent, Match Grade ammunition), actually boosts the weapon's base Acc, so you use the new Acc for things like the skill cap, Precision Aiming, and so forth.

Originally Posted by swordtart

If you lower the ACC of the musket to 1, you can at most add another 1. ACC 2 makes hits at 50 and 100 yards hard, but not impossible, but it quickly shifts the 150+ range shots into the miraculous.

I'd want to get some more concrete numbers on what sort of MoA muskets see before I did this. Granted, a musket that lacks any sort of proper sights should probably have -1 to Acc.

[Ulzgoroth]

There was a thread relating to the 2xAcc cap recently...I'm pretty sure the conclusion was that it applied to aiming aids but not to the +2 for extra seconds of aim. (That is, an unmodified Acc 0 weapon's aim bonuses go 0, +1, +2 for 1-3 seconds.)

Originally Posted by Varyon

Cheap apparently isn't actually an option for firearms - oops.

I can't find a Cheap option either, but GURPS authors occasionally think there is one...

Originally Posted by Varyon

I'd want to get some more concrete numbers on what sort of MoA muskets see before I did this. Granted, a musket that lacks any sort of proper sights should probably have -1 to Acc.

There's a very interesting, though possibly problematic, box on page 41 of Tactical Shooting relating to this. It includes halving Acc for a gun with misaligned sights and reducing it to 0 if the sights are destroyed.

The problem with this, of course, is that there are lots of weapons with no sights and non-zero Acc values throughout the books...

[Varyon]

Originally Posted by Ulzgoroth

There's a very interesting, though possibly problematic, box on page 41 of Tactical Shooting relating to this. It includes halving Acc for a gun with misaligned sights and reducing it to 0 if the sights are destroyed.

The problem with this, of course, is that there are lots of weapons with no sights and non-zero Acc values throughout the books...

In the hands of a modern shooter, giving a weapon without sights Acc 0 may well be appropriate, as they'd be so used to having sights that they would have issues Aiming without them. GURPS characters, as well as shooters at lower TL's, on the other hand, should probably be expected to know how to use the barrel itself for Aiming (much like an archer can Aim down the shaft of an arrow; failing that, I came across one account of a person using the bayonet lug for primitive sighting), although I don't think this should allow for more than Acc 1 or 2.

Originally Posted by johndallman

It appeared in After the End 1, p32, after having been on PK;s MyGURPS site for several years.

Alright, then - that -1 Acc reduces the Range at which scatter comes into play.

Originally Posted by Polydamas

Minutes of Arc are a measurement of a model which was designed to be simple and describe late 20th century firearms, and safisher reminds us that assigning weapons an Acc score in GURPS is a matter of judgement and looking at the stats of similar weapons, not a matter of measuring something. If you check the FAQ, they explain the process- and the kind of testing from a clamped rest which some firearms manufacturers use to measure accuracy in minutes of art would not work for lariats, javelins, and other things with an Acc score in GURPS

Fair enough.

Originally Posted by Tomsdad

Would you do be doing this is addition the the flight time mods from TS?

In addition. Granted, the majority of the shots I'm basing it on had velocities over 400 yards per second (a couple were instead in the mid-300's), and you're looking at 1d-5 at around 200 yards. So, this spreads things out more rapidly. You could probably be forgiven for only using one or the other, however.

Originally Posted by swordtart

I think this is a specific muzzleloader issue and possibly only muzzle-loaders firing round ball(rather than say Minnie Ball).

Yeah, Minie Ball is going to greatly reduce this problem. Lack of spin is going to be a bit problematic, but that's handled well enough by the lower Acc the weapon has for not using a rifled barrel.

Originally Posted by swordtart

No amount of skill can compensate for the projectile having an unpredictable flight path.

You could simply apply a flat rule that says at x range the maximum chance to hit including all modifiers is Y. Y decreases by 1 per additional z range interval.

My suggestion actually does this, when combined with the Minute of Arc rule from Tactical Shooting. A skill cap of, say, 26* means that, at 70 yards, you cannot have effective skill higher than 17, or a 98% chance (although with Malf. 14, that drops to an 84% chance). Using just the MoA rule, that means at 200 yards you cannot have effective skill higher than 14, or a 91% chance. Adding in my suggestion, the low-resolution version means at 200 yards you cannot have effective skill higher than 11 (62% chance). Higher resolutions make this variable, but still average out around 11.

Of course, you don't have to be a master shooter (Skill 20, Braced, Aiming for 3+ seconds, and using an All Out Attack to reach 26) for the ball's scatter to mess you up, which is why I have it as a penalty, rather than just a cap.

*It's hard to find decent data on musket MoA using a few quick Google searches, but from what I can tell they typically have higher MoA than the 5 implied by a skill cap of 26. If we assume MoA 36 is typical of a smoothbore musket (as I saw claimed in several of my results), that's a skill cap of either 20 or 21 (the musket from the thesis, based on performance at 50 yards, appeared to have a skill cap somewhere in the vicinity of 23 or 24). Note this markedly changes to above probabilities - assuming a cap of 21, 70 yards means maximum skill of 12 - 75% - and 200 yards means a maximum skill of 9 - 37% - and my suggested rule drops the 200 yard shot to 6 - 9%. It also means we only need skill 15 - an expert shooter - to be able to hit our cap. As period rifles apparently had MoA's somewhere around half those of muskets (at the worst), that's a cap of at least 23, and helps explain why you'd want a rifle for distance shots.

Originally Posted by swordtart

I also think that it is something that needs to be prepared for in advance by aquiring the equivalent of Match grade ammunition (probably casting it yourself with a custom mould and fettling it). With an imperfect ball, loading carefully won't help. Loading fast with a perfect ball may turn it into an imperfect ball.

Simply properly measuring out the powder (already done for any paper cartridge made by a competent shooter) and having a smooth loading should be enough to see a boost in Acc. Using a perfect ball is below normal GURPS resolution - most balls are good enough for GURPS Acc granularity - but as I noted in my post, it should be an option that increases the range at which you start taking penalties for scattering.

Originally Posted by swordtart

You will also need to load your own in advance. Ordinarily cartidges are mass produced in factories and so are not tailored to a particular gun. This is ideal for regimented armies using a similar bore who want to fire quickly and cheaply, but not so useful for the targeteer who wants to maximise his chance of hitting.

From my reading, GURPS automatically assumes the characters are loading their own cartridges and making their own bullets. High Tech notes that troops typically spent the night before a battle making their own cartridges, while Low Tech states that armies typically just carried around lead ingots, and the troops used these to cast their own bullets (using molding gear specific to their weapons). Using standardized bullets with muskets that aren't standardized strikes me as a losing proposition.

[Polydamas]

One question to ask would be whether the rules for musket accuracy are any worse a fit than for the performance of stones, arrows, or .50 BMG rounds. GURPS rules try to be in the right ballpark while being simple enough for ordinary people to use after a long day at work and without spending more time and book money than GURPS players are willing to pay for.

Originally Posted by Varyon

Fine (Accurate)* is found in both High Tech (p79) and Low Tech (p95-96). Careful Loading is similarly found in both books (p86 and p95, respectively). Cheap apparently isn't actually an option for firearms - oops.

High Tech p. 10 does say that the cheap modifier printed on that page is not available for firearms, but the cheap/good/fine options were created to describe edged weapons, and examples of cheap firearms (and effects of cheap quality, such as dangers using Extra-Powerful Ammunition HT p. 165) are scattered throughout High Tech. My copy of the basic set is in the old country, but a simple way to read this would be that cheap firearms have idiosyncratic costs and disadvantages, such as reduced Malf, rather than stats which can be generated by algorithm from a base entry.

[johndallman]

Originally Posted by Varyon

Cheap apparently isn't actually an option for firearms - oops.

It appeared in After the End 1, p32, after having been on PK;s MyGURPS site for several years.

[Anthony]

The GURPS range rules in general are more of a gameable hybrid than anything resembling modeling of real world performance; firing under controlled conditions is much more reliable and has much faster performance dropoff than the rules in GURPS. This is, most likely, because your skill in GURPS includes effects other than "did you aim in the right place" -- when someone misses at 2 yards, that's not because of the accuracy of their weapon.

[Tomsdad]

Originally Posted by Anthony

The GURPS range rules in general are more of a gameable hybrid than anything resembling modeling of real world performance; firing under controlled conditions is much more reliable and has much faster performance dropoff than the rules in GURPS. This is, most likely, because your skill in GURPS includes effects other than "did you aim in the right place" -- when someone misses at 2 yards, that's not because of the accuracy of their weapon.

If reality is that accuracy in general is maintained for longer but then drops faster past a certain point, that to me that sounds like the underlying issue is how range table spaces the range penalties by distance.

I also quite liked systems that recognise that different weapons/set ups are best suited for different ranges (i.e not just a bonus to all shots which you apply to all ranges)

[Polydamas]

Originally Posted by Varyon

I don't know how far back it goes, but GURPS Acc actually has a close relationship to the weapon's MoA - you can see this in Tactical Shooting, where Acc serves to allow you to calculate maximum effective skill (which is a function of MoA).

Minutes of Arc are a measurement of a model which was designed to be simple and describe late 20th century firearms, and safisher reminds us that assigning weapons an Acc score in GURPS is a matter of judgement and looking at the stats of similar weapons, not a matter of measuring something. If you check the FAQ, they explain the process- and the kind of testing from a clamped rest which some firearms manufacturers use to measure accuracy in minutes of art would not work for lariats, javelins, and other things with an Acc score in GURPS

Its possible that TS uses Acc to calculate maximum possible Aim bonus and skill because its the most appropriate game stat, not because if Hans were building a model from scratch, he would use one number to represent pointability, accuracy from the shoulder over iron sights at medium range, and accuracy prone from a rest at extreme range.