A good high quality .17 or .22 airgun might serve you better- low noise, cheap practice, and less cance a bullet will skip off into the next town.

A good .22 might be one of the bolt action .22's made by CZ (Ican't remember the model). Its an adult sized bolt action that can fire anything from CB caps to Long rifle .22's. I would stay away from autoloaders like the 10/22 if you want to subsonic ammo or anything smaller than 22 LRs for that matter.