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Old 07-15-2020, 02:14 PM   #71
Been
 
Join Date: Dec 2006
Default Re: GURPS ULTRATECH ballistics?

Where is this spread sheet available?
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Old 07-15-2020, 05:46 PM   #72
hal
 
Join Date: Aug 2004
Location: Buffalo, New York
Default Re: GURPS ULTRATECH ballistics?

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Originally Posted by Been View Post
Where is this spread sheet available?
Which one are you looking for? I have both Doug's original and my modified version?

If you want either or both, click on my name and email me your request.
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Old 07-15-2020, 07:28 PM   #73
DouglasCole
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Default Re: GURPS ULTRATECH ballistics?

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Originally Posted by hal View Post
Which one are you looking for? I have both Doug's original and my modified version?

If you want either or both, click on my name and email me your request.
What version do you have, hal? My latest is 2013
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Old 07-15-2020, 08:54 PM   #74
hal
 
Join Date: Aug 2004
Location: Buffalo, New York
Default Re: GURPS ULTRATECH ballistics?

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Originally Posted by DouglasCole View Post
What version do you have, hal? My latest is 2013
Ballistics Model July30-2013

I think you had me resend it back to you a short time back.
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Old 12-22-2020, 07:42 AM   #75
hal
 
Join Date: Aug 2004
Location: Buffalo, New York
Default Re: GURPS ULTRATECH ballistics?

I'm adding this post here for later reference...

In trying to come up with ways to calculate stats for GURPS guns based on real world data, I have the following items to try and work out. Doug's original spreadsheet that I then modified such that one merely inputs the bullet mass, bullet diameter, bullet velocity and aspect ratio - all have some value in calculating Damage values for bullets as well as 1/2 damage range (which will not match up with the official GURPS 1/2 damage range) as well as the following stats as yet unaffiliated with any known formulas:

Recoil
ST
Acc
Blk


Recoil - is essentially a function of the old third law of motion - for every action, there is an equal and opposite reaction.

Gun designs where the "stock" is lower than the axis of force (such as might be found with a Kentucky Rifle for instance) there is an additional element where not only does the object recoil in the opposite direction of the bullet leaving the barrel, but the torque involved and force the barrel tip up as well as back.

For now, the formula I'm using will not examine "design issues" but deal ONLY with the recoil energy going in reverse of the bullet direction. To wit:

Recoil energy = -1 x Bullet Mass * Bullet Velocity/Weapon Mass
Note: the true formula would include the mass of the propellant in grains x its velocity, but, lacking that information, it would be relatively the same issue in all calculations. For example, the 9x19mm P round, would have a propellant mass of about 5.5 grains and its velocity would be about 1.5x that of the bullet's velocity (or about 1250 x 1.5 = 1875). Also note that this "negative" value simply means that the velocity is in reverse of the bullet's direction.

Example: a 9x19mm Parabellum round produced by Speer, would have a 124 grain bullet travelling at 1250 feet per second. Translating grains into actual pounds in weight we find that the bullet's mass is 115/7000 or .0177 lbs x 1250. Plugging this into the spreadsheet that Doug developed, results in a damage of 2d+2. The felt recoil would be -.0177 x 1250/1.9 (weight of the GLock 17) = 11.645 (absent the charge powder weight). If adding the charge powder weight portion of the calculation, we'd get 11.645 + 1.47/1.9 or pretty close to what an online recoil calculator says the value should be.

By leaving off the charge weight and velocity/weapon weight from the calculations, it skews the value by about 7% for the pistol - not sure if that will matter when it comes to comparing rifles to pistols etc. The idea here is to see if there is a relationship to real world data and GURPS HIGH TECH sufficient to calculate a reasonable "Rcl" value for pistols and rifiles using real world data.

If this works, then the spreadsheet can calculate Damage per Doug's formulas, 1/2 damage range per Doug's suggested formula, and possibly recoil per the above correlcation with already published GURPS HIGH TECH weapons.

Later on then, this information would be useful for ULTRATECH weapons.
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