No flashy background.

No flashy text.

Just the formulae for converting Real Life firearms to Silhouette.

First you'll need to determine the Kinetic Energy of a bullet...

 

To determine Kinetic Energy (KE) in Joules,

KE = (m * v^2) / 2000

 

To determine Damage Multiplier (DM) from the Kinetic Energy (KE, as muzzle energy in Joules):

DM = 2 * (cuberoot(KE))

Then, twiddle the DM until you get a value that "feels" appropriate for the given round (e.g. more/less powerful than an alternate cartridge, better penetration, etc.). Remember that Silhouette's Damage Multiplier is nominally a function of penetration, and it's not a linear progression to boot. x20 is not twice as good as x10, it's four times better...

 

To determine Rate of Fire:

Make it up. Assume most handguns are semi-auto only (ROF 0), machine-pistols and assault rifles are ROF 1 (presumably for controllability..?) and SMGs are ROF 2. Heavy weapons can have whatever ROF seems reasonable. Another guideline is that each ROF point connotes roughly a 30rds/sec fire rate. <shrug> Use what you like...

 

For Wierd Stuff (Shotguns, etc)

Check out other examples on the Weapons Compendium for guidelines... To estimate DM for shotguns, use the total mass of the shot when calculating KE, but when determining DM, use only the cuberoot of the energy (rather than 2x the cuberoot). Buckshot also gets a +1 ACC bonus due to the pattern, but generally crummy damage. If you don't mind the bookkeeping, you could also say that Shot ammunition increases the Armor protection of the target (if he's armored) by some value (say, 10), to simulate the reduced penetration.

thanks to uhh...Banzai! He originated the conversion formula on the Heavy Gear Mailing List (HGML), and I unconsciously regurgitated it when I was trying to come up with a formula on my own for converting firearms. Parallel thinking? Or did I just subconsciously remember his equation? <shrug> who knows.
Here's the link to his page: https://banzaidyne.neocities.org/

Note from Banzai, September 2018: This calculation is not the only method I've used for figuring out Damage Modifiers. I've mostly used the rules in Guns, Guns Guns by BRTC Games, particularly when I wrote the Heavy Gear Equipment Catalog. (The Heavy Gear line editor at the time also wrote the Silhouette conversion rules for 3G3, so its use was no surprise.) This article on Banzaidyne provides more information.