Projectiles will be simple aluminum cylinders; lighter weight for hypervelocity, so they punch a perfectly round hole in the target. Think wadcutter impacts. Still spin stabilized with rifling.
The projectiles and powder will be loaded separately into the firearm. The simple, cylindrical projectiles will be in something like a magazine, but the powder will be loaded in bulk into a reservoir that feeds the chamber. Most firearms will still be manufactured for advanced versions of today's powders (principal advances will be in burn cleanliness and in grain shapes that lend themselves well to in-gun metering). There will be some, however, that will use radically different powders that generate higher velocities with virtually no wear of the mechanical components. But you've gotta be a bit of a daredevil to use them; rumors about occasional reservoir detonation persist, especially in the crater where Waco, Texas used to be. The more risk averse technology leaders are getting into one-handed railgun weapons.
Naturally, the 1911 in .45ACP will still be superior to all of these.
The projectiles and powder will be loaded separately into the firearm. The simple, cylindrical projectiles will be in something like a magazine, but the powder will be loaded in bulk into a reservoir that feeds the chamber. Most firearms will still be manufactured for advanced versions of today's powders (principal advances will be in burn cleanliness and in grain shapes that lend themselves well to in-gun metering). There will be some, however, that will use radically different powders that generate higher velocities with virtually no wear of the mechanical components. But you've gotta be a bit of a daredevil to use them; rumors about occasional reservoir detonation persist, especially in the crater where Waco, Texas used to be. The more risk averse technology leaders are getting into one-handed railgun weapons.
Naturally, the 1911 in .45ACP will still be superior to all of these.