I'll tell ya scout, I know how hard it is to find. I've only found two places to get tin that I can trust to be tin. First is Roto. It's high but I've not found another source that's commercial and a business that's got it in stock when you need it. The other place I've gotten tin, and for a lower price is on the website castboolits.com, they have a sub forum called selling /swapping , many members sell pewter and some sell tin. I picked up 5 one ounce bars of 99.5 pure tin for half of what Roto costs. And, if your a caster, it's a casting forum you should join. It's an amazing site for casters.



Here's the five bars plus one ounce of tin wire clipping from Roto.

This might help you. A 20 to1 is going to give you a BHN hardness of 10. You can get the same 10 BHN if you mix equal parts of pure lead and wheel weights. Here's a alloy calculator I use when mixing alloy for different hardness requirements.



Here's the website for the calculator.

http://www.weatherby.dk/bhn.htm

Made a handful of 30-30. 150 gr with w748 powder

How much 748?

Used 1/2 lb of powder on these.... Charge is 233 grains of H50BMG under a 750 grain A-Max



Also about a 1/2 lb on these.