TAYLOR: Who’s stepping on my musket?
KIRK: That’d be me.
A musket is a long gun with a flintlock mechanism, fired over the shoulder, and with musket balls as the ammunition rather than bullets. They were in use from the 17th century, and were the weapon of choice in the American Revolutionary War.
They weren’t very accurate as they didn’t have a sight on them, and took ages to reload. Nonetheless if they did hit their mark they could be deadly, and leave a larger and more complex wound than a modern gun (not to mention the lower standard of medical care victims would have received in the 18th century). Muskets were superseded by the rifle in the 19th century.