To the Doctor Alt 8: Thanks. Were you at Tewkesbury or Kelmarsh this year? Our paths may have crossed. I was (incongruously in the case of Tewkesbury) in Napoleonic redcoat kit for both.
To locust of death: That is far from a silly question. To be honest, I don't know if they referred to the rounds as bullets during the time of flintlocks. I think it was just balls. It was musket ball, cannon ball.
The shot was indeed an often poorly cast lead ball which would come rattling out of the smooth bore of the musket or pistol. When rifling (the spiral grooves in the barrel) was introduced, most notably with the Baker Rifle used by the 95th Rifles (yes, Sharpe and his boys), the spherical ball was wrapped in a leather pad and pretty much forced down the barrel, sometimes even hammered, so it sat snugly in the grooves and came out in a reliable way. This reduced the rate of fire from up to 4 rounds a minute from a musket to as slow as one round a minute from a rifleman, but the accuracy the rifle gave the 95th enabled them to pick off French Officers at 200 yards, while the musket would be lucky to hit it's target at 50.
By the time the three-band Enfield came in, the round, I believe, was bullet-shaped and didn't require a leather jacket, but would still have been muzzle-loaded.
I've had a go at live firing all these, including a flintlock pistol, at a black powder day at a shooting range. And it was awesome. Especially the pistol.