223 is an awesome round for 100m shooting. There's a lot to choose from and the rifles are relatively cheap, at least if you want to shoot bolt-action.
I know punching holes in paper may seem a bit tedious, but with the battleships, darts, pool etc targets that are out now I find you can get a good bit of friendly competition going, and have a lot of fun. I shoot 223 up to 500yds, with varying loads. If you do get into precision shooting you will ultimately want to load your own ammo. That's where the biggest gains in accuracy can be achieved (assuming you have your stance & breathing down pat).
..and yes, I have guys in full tac-gear, vests and holsters etc, show up at the range. They are a little put out when they realize they have to be licensed (black badge) to legally holster a pistol in Canada.