There are a few basic problems of scale associated with this era, though, for man-to-man adventuring. The most obvious is that of range. Here are some typical ranges for 18th century arms, rounded off for easy usage:
- Musket: Point Blank 60 yards / Effective 120 yards / Max 240 yards
- Rifle: Point Blank 100 yards / Effective 200 yards / Max 400 yards
- 3 lb light cannon: Point Blank 200 yards / Effective 400 yards / Max 800 yards
Compare those to your typical medieval game. Long bows vs. point targets are typically effective to about 100 yards. Most hurled weapons are being used far closer, and with indoors scenes dominating, hand to hand melee is king. Moving the action to larger outdoor venues with firearms definitely changes the necessary scale.
The other issue is the rate of fire of such arms. A musket could be fired around 4 times a minute by a well trained regular.
Marshal Maurice de Saxe wrote: "Light infantry should be able to fire 6 shots a minute, but under the stress of battle 4 should be allowed for."
Finally, rates of march remain similar across the eras. The quick time march is about 85 yards/min, and double quick is 150 yards/min. This is actually fairly rapid; it is a 5 MPH pace or a 12 minute mile. Obviously a dead run is faster, but sustaining a 12 minute mile while loaded with gear on battlefield terrain under fire in formation is pretty legit.
With that data in hand, here are some examples of scales that could be appropriate:
1 figure = 1 man, 1" = 10 yards, 1 round = 20 seconds
With this scale, a "quick time" march would cover 3" per round, and a "double quick" about 5" per round.
- I really like this as if you wanted to add a bit of randomness to movement, you could determine move distances with the roll of a D6. For example, at the quick march, roll 2d6 and retain the best; at the double quick, roll 3d6 and retain the best. Double sixes equals a move rate of 7" (8.5 minute miles), and rare triple sixes equals 8" move.
- There is also a happy coincidence that the number of inches of movement equals the rate of move in MPH, which allows for easy conversion to overland adventuring scale. "Quick time" = 3 MPH.
- Horses would cover about 8-10" per round at a trot or gallop, which again is easily derived by rolling a D6+5 and allows similar conversion to MPH.
Conversion of weapon ranges to tabletop distances is easy; divide by ten. For example, musket range would be 6/12/24". Ranges would fit fairly easy on a typical table. A yardstick worth of play area could probably be sufficient for most engagements.
The problem here is granularity of action and reloading rate. With each round being 20 seconds, you need to allow a proficient musket user to load and fire at least once each round. Even that only gets you three shots per minute, which we know is shy of the historical case of 4-6 shots per minute. So clearly we need some sort of provision to allow well-drilled regulars to occasionally squeeze in an extra shot; say, a 1/3 chance per round.
We also need to allow multiple actions per round (load and fire). This is familiar to D&D players of 3E ("move & standard" actions) but I prefer simpler systems where everything is a full round action, personally.
One could do a variation on this for 1" = 10 yards, 1 round = 15 seconds. This would change your march rate to 2-4" per round, but could solve the rate of fire issue.
1 figure = 1 man, 1" = 5 yards, 1 round = 10 seconds
With this scale, again a "quick time" march would cover 3" per round, and a "double quick" about 5" per round. Conversion of weapon ranges to tabletop distances is a bit harder; divide by 20. For example, musket range would be 12/24/48".
The shorter rounds helps solve our rate of fire problem. If we allow load & fire each round, then we get six shots per round; if we throw in some sort of random "x" factor to occasionally mess up the process (say, loading requires passing a relatively easy skill check, but one which is failed from time to time) we can throttle that down to fewer shots per minute fairly easily.
With a more granular system of actions, you could require "load" and "fire" to each be full round actions. That would still allow three shots per round. We'd have to have some sort of "feat" or rules exception for well-drilled regulars that let them accelerate the load & fire process to get back up to our six-shots-per-minute best case, though.
The problem here is tabletop real estate required. Now I need six feet of table to cover most probably scenarios. Youch!
1 figure = 1 man, 1" = 10 yards, 1 round = 10 seconds
With this scale, again a "quick time" march would cover 1.5" per round, and a "double quick" about 2.5" per round. Conversion of weapon ranges to tabletop distances is easy again. Loading is easy too.
The problem here is the move rates are very slow and small. It almost necessitates some sort of battle grid, and even then we'd probably have to either round up to 2"/3" moves, or have some sort of mechanic that allows an extra 1" space to be moved every other round. It would also be very difficult to work in any sort of reduced move rates, say, from difficult terrain.
1 figure = 1 man, 1" = 5 feet, 1 round = 6 seconds
With this scale, again a "quick time" march would cover 5" per round, and a "double quick" about 9" per round. Conversion of weapon ranges to tabletop distances is a bit tougher, as we're going from yards to feet, but you could round the weapon ranges off. Musketry would be at 36"/72"/144" though, which is the fatal flaw of this scale: you need the length of a room just use use muskets, much less rifles or cannons!
This scale does resolve the granularity of action issue in that you could have loading be a full round action, and firing be a full round action, and get about five shots per minute.
Rules Lite Abstraction
You could also dispense with such scales altogether and go rules lite with some sort of range abstraction. Say that characters are either in range, or they're not.
I can see why man-to-man action is not popular to model in the 18th century context, except perhaps for naval battles where these issues are easier to manage!