For quite some time now, I've been advocating for a change to how Rifle Cannons work. The flat -3 to damage for them (regardless of size) results in ZERO damage for the Light (a singularity that is anathema to any game system). I propose the Heavy take -4 (resulting in 5), the Medium take the canonical -3 (resulting in 3), and the Light take only -2 (resulting in 1). The math backing that up is below, based on the AToW page 211 and AToW Companion page 171 formulas. I could have sworn I posted this math before, but I can't find it. 7 AP for the Rifle Cannons is based on them being able to defeat Tech Level C "state of the art" armor, which was BAR 7.

`Heavy`

Assuming 7AP/54BD (6 points BD per 1 point TW scale damage per AToW page 211):

Assuming "splash damage" ammunition and a single shot while using the AToW Companion page 171 formula:

Penetration Factor: 7 AP / 4 = 1.75

Damage Factor: 54 BD * (3.5 + 1 for "splash damage") = 243

TW Damage = PF * DF / 50 = 8.51, rounds to 9 points of TW damage

7 AP is 3 points below 10 BAR, so both AP and BD are reduced by 3 (per AToW page 185), to 4 AP and 51 BD against BAR 10:

Assuming "splash damage" ammunition and using the AToW Companion page 171 formula:

Penetration Factor: 4 AP / 4 = 1

Damage Factor: 51 BD * (3.5 + 1 for "splash damage") = 229.5

TW Damage = PF * DF / 50 = 4.59, rounds to 5 points of TW damage (-4 compared against BAR 7)

Against BAR 8: 6 AP / 53 BD yields 7.16 points of damage, rounding to 7 (-2 compared against BAR 7)

NOTE: The above shows how finely "tuned" the HRC was to the armor of its time.

Against BAR 9: 5 AP / 52 BD yields 5.85 points of damage, rounding to 6 (-3 compared against BAR 7)

Medium

Assuming 7AP/36BD (6 points BD per 1 point TW scale damage per AToW page 211):

Assuming "splash damage" ammunition and a single shot while using the AToW Companion page 171 formula:

Penetration Factor: 7 AP / 4 = 1.75

Damage Factor: 36 BD * (3.5 + 1 for "splash damage") = 162

TW Damage = PF * DF / 50 = 5.47, rounds to 6 points of TW damage

7 AP is 3 points below 10 BAR, so both AP and BD are reduced by 3 (per AToW page 185), to 4 AP and 33 BD against BAR 10:

Assuming "splash damage" ammunition and using the AToW Companion page 171 formula:

Penetration Factor: 4 AP / 4 = 1

Damage Factor: 33 BD * (3.5 + 1 for "splash damage") = 148.5

TW Damage = PF * DF / 50 = 2.97, rounds to 3 points of TW damage (-3 compared against BAR 7)

Against BAR 8: 6 AP / 35 BD yields 4.73 points of damage, rounding to 5 (-1 compared against BAR 7)

Against BAR 9: 5 AP / 34 BD yields 3.83 points of damage, rounding to 4 (-2 compared against BAR 7)

Light

Assuming 7AP/18BD (6 points BD per 1 point TW scale damage per AToW page 211):

Assuming "splash damage" ammunition and a single shot while using the AToW Companion page 171 formula:

Penetration Factor: 7 AP / 4 = 1.75

Damage Factor: 18 BD * (3.5 + 1 for "splash damage") = 81

TW Damage = PF * DF / 50 = 2.84, rounds to 3 points of TW damage

7 AP is 3 points below 10 BAR, so both AP and BD are reduced by 3 (per AToW page 185), to 4 AP and 15 BD against BAR 10:

Assuming "splash damage" ammunition and using the AToW Companion page 171 formula:

Penetration Factor: 4 AP / 4 = 1

Damage Factor: 15 BD * (3.5 + 1 for "splash damage") = 67.5

TW Damage = PF * DF / 50 = 1.35, rounds to 1 point of TW damage (-2 compared against BAR 7)

Against BAR 8: 6 AP / 17 BD yields 2.3 points of damage, rounding to 2 (-1 compared against BAR 7)

Against BAR 9: 5 AP / 16 BD yields 1.8 points of damage, rounding to 2 (-1 compared against BAR 7)