Why does the Lone Ranger use Silver Bullets?
Silver bullets are the Lone Ranger's calling card. Silver is a symbol of purity. On the television show the Lone Ranger says he uses silver bullets as a symbol of justice, but more importantly, silver bullets serve to remind the Ranger of just how heavy a price firing a gun can be.
A side note: The Lone Ranger's horse, Silver, was shod with silver horseshoes!
Okay, so where did he get all of this silver from to make bullets and horseshoes and stuff?
The Lone Ranger had a silver mine that he and his brother, Dan, had planned on using for their retirement. A retired Texas Ranger named Jim Blaine (who knew the Ranger's secret) agreed to work it for him and make the silver bullets. The Lone Ranger and Tonto would periodically visit the old Ranger and stock up on bullets and more silver to use to buy goods. (This mine would be the basis of the fortune that built the Reid publishing empire in the Green Hornet.)