>>63966398
>who the fuck thought this was a reasonable idea
Every soldier who didn't want to be ridden down by cavalry and butchered, anon. The fully-realized flintlock musket with bayonet was the weapon that replaced both the pike and arquebus of the prior era. The gun has to be long enough to deter cavalry when in formation. As for caliber, muskets were smaller in bore than the earlier heavy arquebuses, around .70 caliber rather than almost 1 caliber in diameter. You needed a big projectile to make the most of the black powder charge, maximizing energy wherever possible.