Until the development of the Minié ball in the middle of the 19th century, the main disadvantages of a rifle compared to a musket were a slower reload time due to the use of a tighter fitting lead ball and greater susceptibility to the fouling of the bore after prolonged use - such fouling would eventually prevent loading altogether, rendering the weapon useless until thoroughly cleaned. The adoption of the Minié ball essentially nullified these disadvantages and allowed the rifle to completely replace the musket.