Just to remind everyone what the Founders had in mind with “keep and bear arms,” this is a not untypical weapon of the time of the American Constitutional era, the British “Brown Bess:”
Built and used for over a century, the Brown Bess was a .75 smooth-bore musket. In the hands of a well-trained user, it could fire 3-4 shots a minute. It was terribly inaccurate, with a maximum effective range of about 100 yards and, practically speaking, much less. It weighed more than 10 pounds, and stood just under five feet tall. Because it used loose gunpowder, both for firing the shot and for igniting the charge, it was unreliable in all but the best (i.e. least windy and rainy) conditions. When fired, it gave forth a large cloud of smoke both from the front barrel and, less so, from the priming hole at the back, and kicked back with a heavy recoil. Those characteristics often caused inexperienced users to close their eyes and step back as they fired, increasing the gun’s inaccuracy. The ammunition was carried separately, unready to fire without preparation and loading, and was both bulky and unstandardized.
The Brown Bess was a complicated and difficult to use machine, massively inefficient at its primary task. It was heavy, inaccurate, unreliable, required substantial training, and only really useful in military terms when gathered and fired by the hundreds if not thousands.
In all this, the weapon differs dramatically from the industrialized, standardized, polished, and carefully designed Bushmaster M4.
(The title from the Rudyard Kipling poem)