What do you mean? What is the exact situation? If the Rifleman is attacking (4) a Musketman (D of 4, plus bonuses), the musketman will likely win.
If you are talking about defending versus, say Cavalry, the Rifleman does have a small advantage. Assuming they both have 4 HP (veteran), the Rifleman should have about a 25% advantage (winning roughly 4 out of 5, whereas the Musketman would win roughly 3 out of 5).
If the Musketman has 1HP more than the Rifleman they will perform roughly the same, if the Musketman has 2HP more (elite Musket vs regular Rifleman) the Musketman will actually do about 10% better.
So what's going on?
Cheers,
Shawn