GURPS ranged combat: Napoleonic vs. 1870

[elglin]

This sure isn't an essay on the real changes - it's about how this looks like per the GURPS system.
Let's assume a Joe Soldier (or Hans Schütze, or Jean Fusilier) with Guns-10.
In the Napoleonic times he's armed with a Brown Bess or her continental equivalent with Acc 2. For simplicity, let's say that it allows a fully aimed shot once every 20 seconds. That fully aimed shot is Acc 2, +2 for Extra Aim, +1 for All-Out Attack for a total of Guns-15.
That's a 50% chance to hit a Joe Soldier-sized target at 15 yards. 26% at 30 yards, 5% at 100 yards. His advancing opponent won't be running those 100 yards at the 5 yards/sec GURPS allows him, of course, however, he can manage 2 yards or even 2.5 yards/sec at a fast pace. Assuming that Joe Soldier starts shooting at 100 yards, he's got three shots total, and his opponent has roughly 1/3 chances not to get hit. That's about the efficiency the British had under Wellington - you can break the opponent's charge with fire... but if he's willing to accept the losses, he'll get close and personal. Against cavalry this will be just a couple of shots - which is consistent with how the infantry square was needed to repel a mounted charge.

Fast forward to 1870-s. Now, our Joe Soldier has an Acc 4 rifle, and he's likely shooting prone with the muzzle resting on something. Even with a single-shooter, his shooting cycle is now: Ready (Ammo), Ready(Weapon), 3x Aim, Fire for a shot every 6 seconds. And that fully aimed shot is Acc 4, +2 Extra Aim, +1 Bracing, +1 All-Out Attack = Guns-18. That's a 50% chance to hit at 50 yards, 26% at 100 yards, 10% at 200 yards - and 90% at 10 yards.
Even if his opponent is running at him at the 5 yards/sec GURPS allows, which would require a well-trained person to manage across 200 yards, our Joe has 40 seconds - seven shots instead of three. His opponent would have some 2/3 chances of not being hit in the furthest 100 yards, but traversing the subsequent 100 yards would have less than 1/6 - meaning that only about one in 8-10 would survive to get... to the point-blank shot at those 7-10 yards. Practically speaking, the morale of any advancing infantry would be long broken before that.
Cavalry would probably be able to traverse the distance twice as fast, but as it is a SM+1 target, that 10% shooting would start at 300 yards, and Joe would still be able to put some 5 shots into the onrushing cavalryman. This pretty much turns any cavalry charge over an open field against a line of infantry into the Charge of the Light Brigade: the attacking cavalry may be able to overrun the infantry unit, but will suffer such losses that would make the cavalry unit effectively wiped out.

All that said, one cannot help wonder, what if Pickett's Charge or, indeed, the Charge of the Light Brigade, both absolutely reasonable at Wagram or Waterloo, although not during the Civil or Crimean War, happened in the face of a 1870-s army. Both those assaults, already futile bloodbaths as they were, would be then approaching Great War levels of sheer carnage.