Also want to keep barrel leading minimized. All the Glocks I have shot up to now have leaded badly. I will be casting straight wheelweights mostly. Have some pure, soft lead I can add to the mix to soften it up a little, to get better obturation and barrel seal if necessary. Would like to keep the bullet just sub-sonic, 1000 - 1050 fps or so. May have to go with something faster than HERCO, to make the initial kick-in-the-pants a little sharper, to get the good bullet obturation.