From everything I read here my alloy should be plenty soft enough to mushroom.....but it doesn't really.
I am working on a hunting load for an old rifle and started with coww +1% tin and at just over 1700fps average into water soaked newsprint some had no upset at all to just a slight "riveting" at the nose. Backed off to 50/50 coww/pure +1% tin and now all rivet from slightly to bumping up to just a bit over bore diameter. I would have thought that that alloy at that speed should get a nice shroom head going. All I can think is wet newsprint is not an acceptable medium or it's my tin source, which is electronic solder (96sn, 4ag).
Anyone with wisdom to share?