@Mushroom
one where the character went out and bought a "silencer" for their revolver.
They may have purchased one. It just doesn't work very well.
Another area where rifling became important, and then not so much, is in artillery and armor (meaning tanks). Old artillery was smoothbore, because it was all muzzle loaded. That's why the old time artillery teams had to train and work together. As soon as the round was fired, you had to run the swab down to clear out any remaining powder, otherwise you'd have premature detonation. Then shove the powder bag in with the ram, followed by the ball. On the other end, the sharp spike was shoved into the firing hole to penetrate the bag and get some powder out. Then once the wheels were clear, you'd set it off with the torch. The cannon would recoil backwards when fired, roll it forward, and repeat the process.
Accuracy didn't matter so much as grazing shots did. The original cannon balls didn't have any explosives in them. They didn't need them. They were instead meant to skip off the ground, literally like a flat stone on a pond, hopefully bouncing for the first time about 30 feet in front of the enemy. They'd bounce up, cut through a dozen men or so, breaking bones, tearing off limbs, or just plain eviscerating them, and then bounce again, doing a rinse and repeat.
Grapeshot and chain shot were also designed to cut through large clusters of advancing troops. The problem with smoothbore artillery, of course, was accuracy and distance. The round cannon balls would spin in a random direction, and could literally act just like a curve ball thrown by a baseball pitcher.
Rifled cannons increased both the range and accuracy of the rounds being fired. Adding breechloading capability meant that more modern, explosive rounds could be used. Modern field artillery has an effective range of about 9 miles. Naval guns were also rifled, with the 16" guns on the Iowa class battleship able to send shell weighing 2,700 pounds just over 23 miles. Every 30 seconds.
Tanks started with rifled barrels, but have now gone to smoothbore cannons because they're no longer shooting regular rounds, with high explosive charges. The main round today is nicknamed the 'silver bullet'. In military terms, it's an APFSDSDU round. That little collection of letters means Armor Piercing Fin Stabilized Discarding Sabot Depleted Uranium round. Basically you have something that looks like a regular round, but once it fires, the Sabot (shoe) falls off, and what you have left is a little dart. Instead of explosives, the round relies on kinetic energy to punch a small hole in the armor of the enemy tank. Which makes a larger hole, with stuff flying off inside the enemy tank, turning the inside of the enemy tank into an abattoir.