The Too Fat Lardies are doing the wargames community a great services by publishing modern editions of the 1824 and 1862 Kriegspiel rules. I have charted data from the 1862 edition infantry fire table to consider the professional expectations of the time concerning breachloader performance.
First, performance as a function of range
An easy target is a body of troops advancing in the open; a hard target are men in cover or obscured. The key point here is the knee of the curve between 250 and 300m -- an inch more or less on our table.
The second chart shows the expectations that harder targets get even harder at long range
Now, while the first chart is going to be very different for a chassepot vs a dreyse, I have to ask myself how the second chart will change.