The hollow base of the cone-shaped minie ball (named for French inventor Claude Minié) expanded when the gunpowder ignited, thereby catching its grooves in the interior rifling of the gun and increasing the velocity and accuracy of the bullet. The longer, effective firing range of minie balls also turned mass infantry assaults into mass slaughter until military tactics caught up with the destructive power of the new technology. The ubiquitous minie balls have been collected as battlefield souvenirs ever since.