Musket be a muzzle-loaded, smooth bore long gun, fired from the shoulder. Muskets were designed for use by infantry. In the Golden Age and Late Pirate Era, they were used with all varieties of flintlocks and became light enough to shoot without a fork. All navies and pirates used muskets, even though you rarely see them used in pirate movies. The sharp shooters were posted up in the fighting tops to shoot at the enemy below. Usually of .69 to .75 caliber, they were an effective weapon with a bayonet.
Rifles be a firearm designed to be fired from the shoulder. It has a barrel with helical grooves cut into the inside barrel walls that will make the projectile spin. This spin stabilizes the projectile which highly increased accuracy. Usually designed for a smaller caliber than a musket, with 50 cal being very popular. Rifling of barrels started in the mid-15th century. Rifles were used by hunters n' sharpshooters. The draw back of a rifle was slow rate of fire n' it required a mallet to pound a ball down the barrel, unlike with a smooth bore musket where the ball could be simply dropped down the barrel. So the rate of fire for a musket was 3 to 5 round per minute vs. one round every 3 minutes for the smooth bore.
Carbine be a shorter version of the Musket n' was also called a Musketoon. Musketoons with a flared barrel arrrr called Blunderbuss. The smaller size and lighter weight of carbines made them easier to handle. The barrels were designed to be short enough to be loaded on horse back. This was mostly a cavalary weapon, but was also use on board ship, as it was faster to load. Spanish name for carbine is Escopeta.
NOTE: All flintlock weapon will only work with real black powder n' not with Pyrodex. Pyrodex is a black powder substitute designed to work with percussion cap weapons. It requires a higher temperature to ignite with a flash point of 740 degrees vs 320 degrees for black powder. Black powder is considered an explosive because of this fact, n makes it more difficult to get due to extra safety requirements. The spark from a flint is not hot enough to light Pyrodex, which means you will get alot of misfires.