FYI get good with a rifle because when supply is shot and your town is down to rifles, you need to still be effective. There are a lot of players in this game that can only reliably hit things with an smg, so when their town is down to rifle-type weapons, they either lose their effectiveness or don't even show up to defend.
I still like to play rifleman sometimes even when we have smgs because it leaves more smgs for the players who struggle with a rifle and also is good practice since you are pretty much dead if you don't hit your first shot when you find yourself in a close range engagement with an enemy smg (unless you can quickly take cover, which isn't always possible). Finally, if you get killed with a rifle it's not a big deal since there are so many of them in supply compared to smgs.
If you get good with a bolt-action rifle, you will be good with any infantry weapon (in my opinion).