You Sir are missing the whole point everyone is trying to make in their posts and you seem to know very little about cast bullets and loading /shooting them and how they differ from jacketed. First off and again we all know the bullets started out at .356 dia. And I ask have you measured the bullets that you have loaded and then pulled(have you?) I guarantee after seeing those pictures that they are less than .356 probably more like .353 . So How in the hell does a undersized cast bullet lead a barrel you ask? Simple the bullet is smaller than the groove dia. And as the really really hot gases are pushing it out of the case and down your super smooth lapped barrel at 30K psi of pressure and since the barrel is not sealed (undersized bullet theory again) that gas is actually eroding the alloy as its being forced through that small gap between the barrel too small of bullet and depositing /smearing it on the barrel, This is all new to you isnt it ? Be honest now! Its not the fault of a softer alloy lots of folks shoot a soft alloy at higher speeds without issue Whats causing it is your loading of them ,the crimping to be exact or I should say over crimping. You actually deformed /squeezed down the base of the bullet with the crimp making it smaller than your groove dia. shot them and got leading in your barrel. Hey it happens most of use that cast or shoot lots of cast bullets have experienced it. But dont go blame the bullet caster for your mistake.I'm sure they wouldnt recommend crimping them twice either. As for why the nose deformed when you pulled them simple look how much neck tension you had any cast bullet would get deformed with a collet puller and alot of neck tension. Again your mistake not "bad" bullets . A hard bullet thats undersized will lead the barrel just the same dont believe me load a cast .356 dia. bullet in a 38/.357 revolver and see what happens.