Christmas came early this year

[Kurt]

Hanz.

Maybe I should explain solder a little more. I was in the plumbing trades and in my early years in the trades we worked with a lot of lead and solder. Like making roof flashings and lead pans for showers or any sort of basins.
Lead in the pure form melts at around 620 degrees and Tin melts around 450 degrees
Lead has a hardness of 5 BHN (brinnel hardness number) I don't know for sure what tin is but it's very close to lead. When you mix tin and lead basically solder you can only go so far for maximum hardness of tin/lead alloys is 17 BHN that is at 63% tin and 37% lead known as 60/40 solder. Tin lowers the melting point of lead alloys, eutectic (?spelling) 60/40 solder melts at around 360 degrees F. if memory is still right. We used a lot of 60/40 solder for wiping lead joints (connecting brass spigots to lead pipe) or wiping the joints using sheet lead because of the lower melting point of the solder compared to lead.
The only way you can make tin/lead alloy harder is by adding different elements like antimony, copper, silver, bismuth, arsenic and so on. Just a little bit of antimony like 22 grams and 15 oz of pure tin to 17 pounds of pure lead will hold the ogive of a bullet shot with a load of black powder just as well as 1/15 T/L
Kurt
I hope this clears up the bullet alloy a little better.