Quote Originally Posted by HW55T View Post
A softer metal than tin is in order and if pellets are to be made using a firing process

A mix of tin, copper and zinc using an annealing process is going to make for expensive pellets
A mixture of light metals as suggested is an alloy of bronze or naval brass. Harder than copper on its own. No advantage for our purposes & still relatively light.
The problem we have is that most heavy metals are toxic to some degree, Lead is toxic, copper & zinc much less so, but they are not totally non toxic.
Tin is very light so not a lot of use.
There are only so many metals available on the periodic table to choose from.
Bismuth is often touted as an alternative but anyone who has ever used it in the field will know that it is extremely brittle & will crumble to bits under shock loads. This was often a factor with large shot sizes in early bismuth shotgun loads, you stuck a shell containing 3's up the pipe but when it crunched through the heavy choke many people were acustomed to using the shot turned into 12's or less.
Its a rare metal & heavily used in the nuclear industry so never going to be available in the quantities needed for ammunition.
same with Molybdenum, Its rare & horrendously expensive.

Being realistic the only real alternatives that are available in quantity are Soft iron, Tungsten & maybe Nickel (though that also has some toxicity issues)
So the only viable alternatives to lead will be a sintered Iron,Tungsten/ Nickel head & plastic body (remember Titan black?) Or a Tungsten powder polymer mix, these were used in shotun ammo with success.
Cheap & affordable they are not.