I have a 2 gallon bucket full of bullets that are too dirty to shoot, and I am going to melt them and recast into some thing i can use. There are some .452 bullets and some .308 bullets and some thing that looks like a cross between a bullet and a wall anchor. It measures .355 and I had a friend test it and it is 98.7% lead. the bullets look to be factory made, can I assume that they have enough of some thing in them that they will cast well and be harder than soft lead, or do I need to add some tin(pewter)??