[Low-Tech] Chinese Guns
 

GURPS Low-Tech p. 87-88 has the 'Crouching Tiger Gun' and the 'Long-Range-Awe-Inspiring Gun'.

I'm having some trouble reconciling the stats of these to the rules for stone balls (under 'Bombards' on LT p. 87 and that of 'Multiple Projectiles' on HT p. 172.

There's no information in Low-Tech on the caliber of the Chinese guns or the diameter of the lead shot. Going by what sources I can find on the Internet, the Long-Range-Awe-Inspiring Gun seems to have been around the caliber of a 2-lb cannon, i.e. 50mm, and the half-inch, half-ounce lead balls would be around .50 inch or 12.7mm to 13mm and 200-230 grains.

From what I can find, one common size for Chinese lead balls for multiple projectile loads seems to have been .43 caliber, which would be 11mm diameter balls weighing about 120 grains. It doesn't seem that this size is assumed in the listed stats in LT, however, as that would make the 3.5 lbs. WPS for a load with 100 lead shot too heavy, unless we are meant to assume a 1:1 correspondance between powder charge and shot weight.

The Crouching Tiger Gun has the same WPS for a load with 100 lead shot as the Long-Range-Awe-Inspiring Gun, so it seems that it would be shooting the same size lead shot, i.e. something weighing around 200 grains per shot.

Here's what I can't figure out:

1) How does the Crouching Tiger Gun get Dmg 6d+2 pi++ with a stone ball?
According to the preceding page, LT p. 87, the weapon tables take into account the halved Dmg and Range of stone balls. This implies that the damage of the Crouching Tiger Gun would be 12d+4 pi++ with a single lead ball, which is utterly awesome compared to any other 47 lbs. firearm, let alone one that costs only $650.

2) Why does the Long-Range-Awe-Inspiring Gun only have average Dmg 0.5 point higher than the Crouching Tiger Gun?
According to the Internet, the Long-Range-Awe-Inspiring Gun fires a 2-lb lead ball with an 8 oz. powder charage. Even if that's inaccurate, the WPS is 3 lbs., so it's reasonable to assume a 14,000-17,500 grain lead ball and 3,500-7,000 grains (8-16 oz.) of propellant. The listed Max Range is 1,200 yards.

The Crouching Tiger Gun has WPS of 1.15 lbs. That means a weight of less than a pound for the stone ball, even if the gun were only loaded with the 3 oz. of powder that a quick Internet search suggests for it. I actually can't find any mention of stone balls for the Crouching Tiger Gun (all I can find are for older guns), so I don't know the specific weight, but with this WPS, it can't be heavier than 1-lb.

How does a lead ball of 2-lb or more, travelling fast enough to reach 1,200 yards, not penetrate better than a stone shot that weighs less than a pound, which doesn't reach more than 550 yards?

Also, how does this fit in with the halved Dmg for stone balls from LT p. 87?

3) How do the 13mm lead shot get Range 130/1,200?
According to HT p. 172-173, 'Canister (TL4)' gets 1/2D Range is (diameter of bullets in mm) x5 and Max Range (diameter of bullets in mm) x50. To get 1/2D 130, the diameter of the lead shot would have to be 26mm. On the other hand, the 'Multiple Projectile' rules on HT p. 172 state that number of projectiles (NP) cannot exceed (weapon's caliber/projectle diameter), so in order to fire 100 lead shot of 26mm, the Long-Range-Awe-Inspiring Gun would have to have a caliber of over 120mm.* Also, 100 lead shot with a 26mm diameter would weigh over 20 lbs., while the WPS is only 3.5 lbs.**

4) How is the Dmg for the lead shot figured?
Using the 0.10 NS modifier for 100 projectiles from the table on HT p. 172, I can't get Dmg 1d-1 pi+ for either the Crouching Tiger Gun or the Long-Range-Awe-Inspiring Gun.

If I simply multiply the NS by the damage for a stone ball in the Crouching Tiger Gun, I get 2.3 (6d+2=23; 23*0.10=2.3). Follow the rules on 'Adjusting Damage' on HT p. 166, that comes out to 0.657 die or Dmg 1d-2. But since these are lead shot, I probably shouldn't be using the halved Dmg from a stone ball as the basis. Doubling the Damage for using lead ammunition comes to avg. Damage 4.6, 1.314 dice or Dmg 1d.

Multiplying the Damage of the Long-Range-Awe-Inspiring Gun with the NS 0.10 yields avg Damage 2.35 (7d-1=23.5; 23.5*0.10=2.35), which comes to 0.671 die or Dmg 1d-2.

*Which it clearly doesn't, both according to the sources on the weapon and common sense, in that's larger than the bore of a 12-lb cannon and the weapon weighs only 160 lbs.
**Which is consistent with around 8 oz. of powder and 100 lead shot of around 12.7mm-13mm and 200-230 grains, with an exact calculation assuming that powder charge yielding 210 grains per shot.

Re: [Low-Tech] Chinese Guns
 

Can some of these discrepancies be explained by the status of these guns as Bombards?

If so, what assumptions are it that differ some materially from the underlying assumptions of the rules for other guns?

In any case, pictures I can find of these Chinese Guns do not appear to rule out using them for direct fire. Should these stats apply to direct fire as well?

Re: [Low-Tech] Chinese Guns
 

Hmmmm, never paid attention to the firearm stats in Low-tech before. I'll take a hard look at them when I get some free time (which probably won't be till Friday). Though I have to wonder if they used David and Han's gun design system for stating them.

Re: [Low-Tech] Chinese Guns
 

Except for the P class errors I've mostly noted them in my head as "don't work well enough to be worth the effort of carrying around".

Any eccentricities of performance could be explained by inefficient design (i.e. the makers didn't know any better) unless they work too well which could be explained by a game designer trying to make them even marginally useful.

Even if these things existed in a setting I was GM'ing what I'd tell player whose character saw one demonstrated was that they appeared to be less useful than large firecrackers.

Re: [Low-Tech] Chinese Guns
 

I'm thinking you're right here. I did some quick number running and found it hard to get 6d+2 worth of damage for the crouching tiger cannon without bumping the muzzle velocity up to almost 1,000m/s! And that's before halving the damage!

Now my damage formula is still incomplete so there is a chance I might be missing something but given that it has come within 20%-30% of most of the damage GURPS assigns guns so far I still think something is off. I'd peg it as doing maybe 3d+1 at most if you ignore the halving.

Re: [Low-Tech] Chinese Guns
 

I did in fact use David's system for every gun in Low-Tech. Unfortunately, my design notes are no longer with me, after two moves, one to a different city. I do have a draft version of David's system on my hard drive, but I would have to review it—and that's not going to happen now, as I have work deadlines staring at me.

Re: [Low-Tech] Chinese Guns
 

Oh, I didn't now you did the gun stats in Low-Tech. Learn something new every day heh.

Ok, since you used David and Han's system that means there must be a factor I'm missing from my reverse engineering of the damage formula. Just knowing this on it's own is helpful.

But yeah, go handle your work. If you do have time at a later date to look over things that would be cool but I personally trust your judgment so it must be something that we're overlooking.

Re: [Low-Tech] Chinese Guns
 

The halving noted on LT p. 172 is presumably meant to account for the lower density and thus the much lower mass of the projectile than if it were lead. I'm pretty sure that you shouldn't apply it if you're calculating the damage using an equation which already accounts for velocity, mass and the diameter of the impact surface, such as Douglas Cole's Ballistics spreadsheet.

Of course, a velocity approaching 3,000 fps from a black powder weapon is extremely unlikely. The highest I've heard for a black powder weapon is 2,400 fps and that was a modern weapon expressedly designed to maximise velocity with black powder, hence unlikely to be achievable at early TL4. For one thing, the velocity of the exploding gasses in most black powder mixtures actually used for historical weapons at the time seems not to have exceeded 2,000 fps very much.

The highest muzzle velocity I've heard argued for period pieces at TL3-4, that is before what GURPS calls TL5, would be 1,500-1,600 fps and even then, that would be exceptional indeed, if it's indeed true that such velocities could even be achieved without TL5+ chemistry. Most black powder weapons were subsonic and those that weren't do not seem to have much exceeded 1,200 fps at TL4 and 1,700 fps at TL5.

I would not be surprised if the Dmg 6d+2 pi++ is a mistake, in that it fails to account for the effects of a stone ball. Dmg 3d+1 pi++ is much more probable and more in line with other black powder weapons.

Re: [Low-Tech] Chinese Guns
 

Ah, then the 3d+2 pi++ (the 3d+1 was a typo) seems about right since my current model takes density into account.

Re: [Low-Tech] Chinese Guns
 

What is the weight of projectile and velocity that you are assuming for that Dmg? And what is the caliber of the ball?

Re: [Low-Tech] Chinese Guns
 

Since it's an iron ball that weights 0.52kg that gives us a roughly 25mm diameter given that iron is about 7.8g/cc.

200m/s was the velocity I used to get 3d+2. That is a bit too high for my taste but if we assume that figure in the book was correct for a normal density bullet and they forget to half it then I suppose it works, in so far as my model is right in the first place.

Hopefully we'll be able to find source that covers how fast it's muzzle velocity was to get more concrete data.

Re: [Low-Tech] Chinese Guns
 

The Crouching Tiger Gun is supposed to have a WPS (Weight Per Shot) of 1.15 lbs., which is the combined weight of the propellant and the stone shot. I don't know what kind of stone, though I've seen sources on Turkish guns mention marble balls. In any event, it must be a tolerably dense stone, but not so dense that it cannot be worked into a round shape without unreasonble effort.

Marble has about a third of the density of iron or 2.563g/cc, so there's a benchmark you could use. Granite at 2.75g/cc makes fairly little difference. Basalt, at 3.011g/cc would be noticably denser and mean a slightly smaller ball.

I would be hesistant to use a 25mm caliber, as it would be rather difficult to fit 100 lead shot of .43 inc to .50 inch there. In fact, it would be entirely against the rules in HT p. 172 for multiple projectiles. Even if we were to assume the smallest .43 caliber shot (which would contradict the WPS as well as Range), we still could not fit more than 12 and that only with great good will and some minor frowardness at rounding.

In any case, there is absolutely no way that the projectile could weigh 0.52 kg, as that would mean that there were less than 25 grains of black powder propelling it. A more plausible powder charge would be the 3 oz. (1312.5 grains) charge that unidentified people on the Internet attribte to the Crouching Tiger Gun by citation to a 1994 volume of Joseph Needham I can't access or the massive 8 oz. (1/2 pound = 3,500 grains) charge that Joseph Needhams assigns* it in his 1987 volume I can read.

This would leave 4,550-6,737.5 grains for the possible weight of the round stone ball or 0.65-lb to 0.96-lb in GURPS terminology, 0.295 kg to 0.435 kg in civilised units.

With marble, that gives me a caliber of some 60.5mm to 68.7mm, depending on the powder charge. The lower bound of this caliber range also fits exactly with the rules on HT p. 172 used to calculate the maximum number of multiple projectiles or the cube of (barrel diameter/shot diameter).

Granite and basalt have a similar range, going roughly 59mm to 67mm and 57.5-65mm respectively, depending on how much of the 1.15 lbs. load is stone and how much is powder.

Personally, I should be inclined to estimate that a lower powder charge would be used with stone shot than lead and thefore essay the 3 oz. charge with the stones and save the 8 oz. one for the lead shot. Depending on the type of stone, I should then have a projectile which took the form of a 0.435 kg stone with a diameter of some 65mm to 68.5mm. If we want to go with the same 8 oz. powder charge for both stones and lead shot, we'd get a 0.297 kg stone ball with a diameter around 57mm to 60.5mm.

If we want 6d+2 pi++ with either load, we have to accelerate it to between 730 fps and 870 fps, depending on our assumptions for stone type and amount of propellant. This is not impossible, to be sure. With a heavy load and good powder, black powder weapons achieved this and much faster velocities too. And even the 'light' load of 3 oz. of black powder is more than three times the heavy load of a 4-bore elephant rifle.*

The mystery then becomes why the Long-Range-Awe-Inspiring Gun, with a 2-lb to 2.5-lb lead ball of diameter from 54mm to 58mm, cannot get more than a 2.2% improvement over this damage. This will occur if we can keep the velocity under 500 fps, I believe, but as to why 8 oz. of black powder should not answer for more velocity gain than that in a 3' barrel compared to a 2' one (especially if we are assuming a 3 oz. charge in the smaller gun), I must admit perplexity.

Also, if the Crouching Tiger Gun can handle that weight of shot and blazing velocity, why build a gun with an identical role and little to no improvement that's 33% longer, more than 240% heavier and almost 240% more expensive?

*With no doubt correct translation, but yet I shudder to think of a 47 lbs. gun firing almost three pound of lead shot with a half pound powder charge and question why where would be any need for the more strongly built Long-Range-Awe-Inspiring Gun if this heavy charge were not considered somewhat over-reaching for the smaller gun.
**Albeit early TL4 powder vs. mature TL5, so that the relative TNT equivalnt measured after correcting for REF might merely be as little as 2 to 1 in favour of the bombard.

Re: [Low-Tech] Chinese Guns
 

Ah, I mistook the listed weight as just being the shot and I must of miss read the stat line since I thought it was an iron ball that it shot. When I get home from work later tonight I'll go over it again and look over the gun section of low tech more carefully, my calculation was based on a really quick glance over I did while getting ready for work.

Re: [Low-Tech] Chinese Guns
 

Ok, now that I've a chance to look over things I've noticed I made a mistake with my diameter assumption, I accidentally used the radius in my calculation rather then the diameter. That's what I get for trying to rush something out before I got the time to sit down and think >.>

I ran the numbers for the Long Range Cannon based on the lead shot weighing 1.19kg and was fired at your estimate of 152m/s with a diameter of 58.4mm and a density of 11.34g/cc. This gives me 17.4 dice with my formula. I ran it again with Doug's and got 15.5. If I ignore density for my formula I get 15.4 dice.

In order to get the books number of 7d-1 or 6.85 dice the gun could only fire at 71m/s!

Given that the numbers I'm getting is roughly twice as high, I wonder if Bill accidentally halved the Long Range Cannon and left the Crouching Tiger one at full damage.

Re: [Low-Tech] Chinese Guns
 

OK just going by comparisons to other guns* in the book (so not commenting on the maths).

That would make the 160lb awe inspiring gun 14d, considerably more efficient by weight than any other gun in the book. In terms of damage the nearest comparisons being the 15d Saker that weighs 1400lbs, the 14d+1 3lb cannon weighs 1000lbs

Now don't get me wrong these guns are not identical, but that's a massive improvement (which I don't think can just be covered by the fact the saker and 3lb cannon have wheels) with really a reduction in range to compensate?


If anything isn't it more likely that the crouching gun's stone shot damage didn't get halved?

As again if you look at it nearest direct comparison the swivel gun (which doesn't have a wheeled carriage) its doing the same damage with stone shot as the swivel gun does with metal and weighs a quarter of the swivel gun weight!

And if you compare it to the wall gun which is a bit lighter but does 5d+1, having the 6d+2 figure being for lead makes sense as well

Or maybe the Chinese once they got into TL4 just made absolutely amazing cannon compared to everyone else (but I don't think that's backed by history)


*which of course begs the obvious question were the discrepancy is.

Re: [Low-Tech] Chinese Guns
 

That's quite a lot, considering that my estimate of 500 fps was derived from at what velocity Doug Cole's Ballistics sheet gave a projectile of that size Dmg 7d-1.

Granted, 1.19 kg for the lead ball is slightly heavier than I had modelled, as I tried lead ball from 2-lb to 2.5 lbs. (0.9 1kg to 1.13 kg). Remember, the WPS of 3 lbs. includes the propellant and that propellant is at minimum 8 oz. or 0.23 kg, according to sources on the Long-Range-Awe-Inspiring Gun.

But this is not enough of a discrepancy to explain such a wide range in the calculated damage. I'm using a version of Doug's file from February 24th, 2011.

This is how my assumptions look:


Note that Chamber Pressure and Burn Length are not necessarily historically right, but it doesn't matter, as they are only set up to produce the right velocity. One might be higher and the other lower, as long as velocity comes out the same.

With this size ball, I get Dmg 7d-1 at velocity 450 fps. If I go down to a smaller ball of 2-lb, I need velocity 500 fps for the same damage.

That seems too high a damage for such low velocity.

I'd think that the Crouching Tiger Gun is more likely to be wrong, as the Long-Range-Awe-Inspiring Gun actually has plausible enough stats at 450 fps, very similar to a Swivel-Gun.

Re: [Low-Tech] Chinese Guns
 

Oh yeah, this all just blind guess atm. I was originally thinking that Awe Inspiring was accidentally halved and the Crouching Tiger wasn't but it is also possible that the Awe Inspiring is right and the Crouching Tiger is still a typo.

And that is what's driving me nuts heh.

Re: [Low-Tech] Chinese Guns
 

I don't know if open office is just acting buggy or if I made a mistake somewhere but I created a new spread sheet just to be sure and ran the numbers using Doug's formula again and I got 6.7 dice. I'm still getting double the damage with my number so I think it's clear that my formula must be off. Welp, back to the drawing board I go.

But at lest I think it's pretty safe to say that that Crouching Tiger Gun stats are in error.

Re: [Low-Tech] Chinese Guns
 

Yeah, a lot of comparing variables against variables here!

Re: [Low-Tech] Chinese Guns
 

Yeah, but at lest we made some progress though it sucks that I didn't end up helping as much as I thought I was. Thought my model was getting really close but it seems that I made an error somewhere on my test sheet. Thank god I didn't use it for my GURPSday post!

This is one of the reason I don't like the "closed box" mind set that 4th editions has had. It's hard to have a generic system if I don't know how to play with it's numbers (though don't get me wrong, I do understand why they felt pressured to do so. I just don't like it heh).

But now that we're pretty sure that we've figured out what's going on with the Crouching Tiger Gun, it's time to move on to why the scattershot range is different from what High Tech suggests.

Re: [Low-Tech] Chinese Guns
 

Not to mention why a full-caliber lead ball has the same range as 100 smaller sub-caliber shot from the Long-Range-Awe-Inspiring Gun.

Re: [Low-Tech] Chinese Guns
 

Ok with the Long Range Awe Inspiring Gun, if we assume that your assumption that it's got a caliber of 58mm and that the damage of 7d-1 is correct then that means each scatter shot round is about 12.7mm which, if we treat it as shotshell, gives me a half damage range of 63.5 and max range of 1,270 and 0.67 die of damage. So it looks like everything adds up... except for the half damage range. So either Bill either accidentally use NP×10 for the half damage range or the Gun Design System rules for scatter shot had changed since High-Tech.

Now to figure out what's going one with the Long Range Gun's range with a full sized shot, I ran the numbers through Doug's spread sheet (I have the 2013 version). This got me a half damage range of 884 and a max range of 3,222. Doug's sheet does give different values for range then the formula used in house, but it is within the same ball park so I think it's safe to say that the range listed in Low-Tech is a copy past error.

Re: [Low-Tech] Chinese Guns
 

Yeah, it would be nice to have both, as you an always use teh one you personally want. I knew at one point there was an armourer's book suggested (maybe as part of VDS) but I don't know of that still going ahead. It would have the similar commercial issues as VDS.




I always assumed that was a typo on the page as you basically have three sets of range stats repeated (but that doesn't actually answer the question I realise)

I think part of thr problem i not actually knowing what these guns are. Which would help with working backwards from reality.

So for sample I can look up a brown bess musket etc, but what's a crouching Tiger gun and what's a Long-Range Awe-Inspiring Gun (and more importantly what's the difference). Of course as has been pointed out this is not the era of standardisation and not only is there overlap of terms but terms were also nebulous and variable etc.

Re: [Low-Tech] Chinese Guns
 

The Armorers's Handbook is going to be separate from the VDS, assuming it comes out at all.



Yeah, knowing what data Bill used when he stated out these guns will help greatly. They both are real historical Chinese guns, the problem is most sources I can find on them is very vague on hard facts like caliber, muzzle velocity and weight of the shot.

Re: [Low-Tech] Chinese Guns
 

Cool. I haven't head about it for a while, so I assume it's a gleam in someone's eye /excel spreadsheet at the moment






True, or even a description. Although given the sheer amount of stuff in that book I'm guessing space was at an absolute premium and word count was a harsh mistress!

FWICT the Crouching Tiger gun is short angled gun pinned to the ground, much more like an older bombard,

The Awe inspiring cannon is vase shaped thing longer and heavier then the crouching tiger but seems earlier (I have to say I assumed it was later).


However that's 5 seconds and Wikipedia, I'm guessing Bill Stoddard did rather more than that when looking at this!


One other think I meant to mention earlier there doesn't seem to be stats for earlier gun powder weapons firing arrows, could probably mash something up from the Flechette rules in HT

Re: [Low-Tech] Chinese Guns
 

Note that we do not treat low-tech multiple projectile loads as 'Shotshell', we treat them as 'Canister' (TL4), which means that Max Range is 50 x diameter of shot. That means that the Range should probably be 65/650.*

*Though I have no objections to slightly altering the results of applying the High-Tech generic rule to match specific historical performance. If another Range statistic can be shown to represent reality better, I'm all for it.

Doug Cole's spreadsheet measures how far a given ball will fly whereas GURPS Max Range is supposed to be a range at which the weapon is still effective, albeit difficult to use. GURPS produces much shorter Max Range scores than the spreadsheet, but that's okay, as otherwise weapons could do half damage out to ranges where they are no more than mild hazards that sting when they hit.

Meanwhile, 1/2D Range in GURPS is not exactly the same as the range at which a given projectile has either half the velocity or energy it had at the muzzle. It seems to be a number meant to reflect differences in 'effective range' between weapons and one might even suspect that there's a lingering taint from where it was the range at which weapon Acc no longer counted. In any case, correcting GURPS rules is all well and good, but it has to happen with consistency. As long as all other weapons use these assumptions for the Range stat, it would create perverse incentives to use a different set of assumptions for one or two weapons.

Note that TL5 Napoleon twelve-pounder cannon is listed at Range 400/2,000* in GURPS. No smoothbore cannon firing round ball has a better range than this. It would be strange indeed if a much ligthter, smaller gun, with a fairly light powder charge for the TL, achieved much better Range than any other smoothbore.

*Artifact the position of the gun, theoretical Max Range 3,300, according to HT.

Re: [Low-Tech] Chinese Guns
 

I don't know if the flechette rules would be a good fit since the rules assume fairly high density projectiles... but for now it would be better then nothing, the ranges would probably reduced, maybe by around 65% or more based on the density of the wood used.


I did look at canister at first but something about the numbers seemed "buckshot" to me so I stated them up using those numbers. Maybe Bill thought the same way or just used the wrong formula.

As to if these numbers fit reality better, that I can't say yet but like you I do think stating them as canister shots does makes more sense.

Yeah, Doug's sheet assumes modern guns so it doesn't take rifling into effect and is calibrated more towards rifles side of ballistics so the numbers it produces for smoothbore low velocity cannons is going to be off but it can at lest give us some rough ideas.

Actually I just re-read the rules for using lead shot and looks the the range for the Awe Inspiring Long Range Gun might be 123/1,124, assuming of course that the range for the Crouching Tiger Gun is correct. This is based on the fact the rules say that lead shot has twice the range and that the Long Range Gun does about 1.02× more damage. Under normal GURPS conventions, this should be rounded to two significance figures or a range of 120/1,100.

So this only muddles thing further for the lead shot figures... did Bill just round the range for the Long Range Gun up? Or did someone made copy paste error given that the ranges were so similar? Or was the range rounded up and it was also used for the lead shot ranges on accident?

Re: [Low-Tech] Chinese Guns
 

That's a good point (I'd forgotten how high the range would be with even the the smallest arrows)