[Kromm]

Because early rifled weapons (late TL4) lost a lot of muzzle energy to deforming the projectile in the name of accuracy. Doing that efficiently was a challenge through late TL5. Just blasting away with things like Acc 2, Range 60/630 weapons and then drawing steel was pretty much the norm for a long time. Tactics needed to adapt to using things like Acc 3, Range 550/1,650 weapons before any real effort was made to make those weapons efficient.

So early musketeers have to decide whether their priority is getting close to people in cuirasses and killing them with pistols, or hanging back and sniping unarmored people and turned backs. Of course, they could also carry weapons suited to doing both.