Basic Information
The minié ball was a - moderately sucessful attempt to fix the obturation problem1 in muzzle loading rifles.
Simply put, the minié ball had a cavity in the base, the walls of which were forced outward by the exploding propellant on firing. These expanding "skirts" sealed the gap between the ball and the barrel, obturating it and allowing it to grip the rifling. This allowed rifles to be worked at almost the same sort of rate as smooth bore weapons whilst retaining their range and accuracy. As a side effect of this design the bullets were large in calibre and cast from soft lead, therefore inflicting large, messy wounds.
Despite a relatively short lifespan - from its invention in 1847 to being rendered obsolete by breech loading weapons in the 1860s - it achieved a high degree of prominence because of it's use in the Crimean War and the War Between the States where it highlighted the growing obsolescence of the 'massed infantry' tactics of previous centuries.
Sources
The other wiki on the Minié ball and, thereafter the Minié Rifle, built by the inventor specifically to use it and including what appears to be before and after pictures illustrating why you should never put any part of your body against the muzzle of your weapon.
Game and Story Use
- PCs could encounter this at either end of its lifespan - either when it is the latest thing and a massive upgrade to their firepower or as an obsolete technology, decades later as war surplus, perhaps on the American frontier or in the African or Asian bush country.
- Note, however, that many users converted their minié firing weapons to primitive breech loaders so a relatively small number of them were sold on - however the massive reduction in the size of the American armies after the War Between the States (for example) would have wielded a large number of unconverted weapons which could turn up virtually anywhere.