CONSIDERATIONS TO KNOW ABOUT 38 SPECIAL CASE

Wow I acquired something critical from this matter. Great thing I didn't go along with the initial powder charge I intended to use. It would have been too sizzling. I'm going to begin with 3.8 grains.I just purchased some 158 gr SWC bullets that happen to be pure lead. How can I inform if they are cast or swaged?for reloading is just not NEW brass,