why do you have to mix tin with the lead... why cant you just make the bullets out of pure lead. I know they would be softer... whats the downside of that just shooting paper..
There are a LOT of factors in the question you are asking. Lead and lead alloys have attributes that you need to understand fully. Lead maintains integrity up to certain pressures. Once you exceed those pressures, it starts coming apart. Tin strengthens it to a degree. Antimony helps. That's the radio version. Go to the top and spend some serious time reading "Bullet Casting 101", then spent some time over at castboolits.gunloads.com for additional follow-up. Read--read--read some more on both sites.