[Low-Tech] Chinese Guns

[The_Ryujin]

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.

[Tomsdad]

Originally Posted by The_Ryujin

...

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.

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.

[The_Ryujin]

Originally Posted by Tomsdad

OK just going by comparison 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?

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.

Originally Posted by Tomsdad

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

And that is what's driving me nuts heh.

[Tomsdad]

Originally Posted by The_Ryujin

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.

Yeah, a lot of comparing variables against variables here!

[The_Ryujin]

Originally Posted by Tomsdad

Yeah, a lot of comparing variables against variables here!

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.

[Icelander]

Originally Posted by The_Ryujin

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.

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.

[The_Ryujin]

Originally Posted by Icelander

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.

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.

[Icelander]

Originally Posted by The_Ryujin

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.

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:

Chamber Pressure --	1090 	psi
Barrel bore -------- 	59	mm
Case Length --------	30	mm
Chamber Bore ------	60	mm
Barrel length -------	610	mm
Bullet Mass ---------	17500	grains
Aspect Ratio --------	1	L/Bore
Burn length --------	300	mm
Projectile Caliber ---	58	mm
Total Accelerated Mass	17500	grains

Velocity ---	137,1	m/sec
 -----------	450	feet/sec
Kinetic Energy	10657,7	Joules

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.

Originally Posted by The_Ryujin

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

That seems too high a damage for such low velocity.

Originally Posted by The_Ryujin

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.

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.

[The_Ryujin]

Originally Posted by Icelander

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:

Chamber Pressure --	1090 	psi
Barrel bore -------- 	59	mm
Case Length --------	30	mm
Chamber Bore ------	60	mm
Barrel length -------	610	mm
Bullet Mass ---------	17500	grains
Aspect Ratio --------	1	L/Bore
Burn length --------	300	mm
Projectile Caliber ---	58	mm
Total Accelerated Mass	17500	grains

Velocity ---	137,1	m/sec
 -----------	450	feet/sec
Kinetic Energy	10657,7	Joules

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.

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.