I have some 158gr cast bullets that are .359 with some black tar stuff around one of the rings. First, is it safe to shoot these bullets in a .358 and second what is the black tar stuff? powdr
Yes. That stuff is most likely some kind of lube.
The old black Lyman lube was beeswax and graphite. They should be safe for use in the .358 for light loads up to 1500 fps or so. A light charge with say 10 grains of Unique will put a smile on your face.
yep, good to go, flair the case a bit more so they don't scrape when seating.