Greg from Canada emailed me an idea. He proposed creating a 360 degree rotatable musket barrel with cuts perpendicular to the path of the ball that would impart a spin on it. If a ballistic computer controlled the rotation of the barrel, the bullet could be fired in a way similar to the Angelina Jolie movie Wanted (2008) where bullets were fired at multiple targets by spinning them around corners.

Greg wrote …

I’m far too old to start tinkering with firearms designs myself, but
in listening to many years’ worth of talk about shooting around
corners, I keep coming back to a simple design using balls instead of
bullets, plus a special type of barrel.

In order to make this work with consistency, you’d need a setup with a
built-in range-finder, a built-in computer, plus you’d need a separate
spotter and shooter; the spotter for finding the target in
3-dimensional space, and the shooter who must rely on the spotter’s
information, simply because in many or most cases he wouldn’t have the
target in view.

The design of the interior of the barrel is what would make this
possible, and the barrel itself must be able to rotate 360 degrees.

Instead of rifling, the barrel must have parallel lines cut in a
straight line in order to put spin on the ball. If turned to the
bottom, the ball would drop like a rock. If put on top the ball would
gain hang-time depending upon the rate of backspin. If turned to
either side, the ball would drift to one side or the other in a
variable arc.

I tried this many years ago, with some pretty primitive equipment, but
it was enough to show that you can make a ball break to the right or
left. My buddies thought it was hilarious that I was able to make the
thing “miss the target” by such an extreme degree, and I couldn’t make
them see the possible advantages.

We didn’t have today’s high-tech range-finders or computers or CAD
programs or CNC’s in those days. If I was young and had it to do all
over again, I’d make something that could pick off an enemy soldier
from around a 40-degree angle; enough so that he wouldn’t know where
he was being shot at from, which would be a great advantage in
warfare.

I was using a muzzle-loader back then, but substituting a ball for a
bullet in a shell isn’t a problem. Plus a hardened ball can do many
things a bullet can’t. The penetrating properties of steel balls are
very much unlike the penetrating properties of bullets. We found out,
purely by accident, that ball-bearings will pass through a pane of
glass without breaking it, whereas a lead ball smashes glass because
it flattens on impact. We also found out that ball-bearings will
penetrate thicker sheets of steel plate than lead. And if the bearings
had high explosive inside, that penetrating-power would increase
greatly.

Anyway- thought you might find this interesting, and fun to try out
for yourself.

The downside of this idea is that it would only work for balls, not bullets, which are inherently inaccurate. It also would be incapable of firing straight. It is easier to lob a 40mm grenade into the vicinity of the area that spray bullets around the corner of a building … but still, its an interesting idea.