Bad idea. Very bad idea.
First, you're putting airborne lead into the house. The lead comes from the primer compound and the base of the bullet. If you use TMJ (i.e., plated) or JHP, the base of the bullet is covered so that will reduce the airborne lead somewhat. Non-toxic, lead-free rounds are available, but they cost ~3 times the cost of standard ammunition and the shelf life of the lead-free primers is suspect.
Second, you're dispersing unburnt powder all over your basement. Try this: go to your local gun club with a broom and a metal dustpan. Go the indoor range and gently sweep some of the dark-looking dust off the floor into the dustpan. Take the dustpan outside, well away from anything flammable. Standing as far away from the dustpan as you can, drop a lit match into the dustpan. Woooosssshhhh! Is that what you want all over your basement? And if you had a house fire, would your fire insurance still be in effect?
Get an airsoft gun or an airgun for practice in your basement. Don't shoot live rounds.