There's nothing wrong with reclaimed lead, just watch the source. Wheel-weights are hard lead that is lighter and doesn't flow as well, but can be mixed with softer/purer/pure lead to improve it's characteristics.
I get a bit of lead from bullets from the local outdoor pistol range, and the lead in bullets is most-usually soft and pure. Clean and let dry, melted, remove jackets, flux...good lead. MidwayUSA used to (not sure of current status or stock) sell Lead Shot, some even included free freight, but You're in Canada so that's an possibly issue there.
Local Pistol Range or Scrap Yards will possibly be Your best bet.