I ran across a guy selling these on the net: 30cal 168 Gr BTHP It made me wonder what a 30cal was. I looked on Hornady's website and it looked like a 30 cal is a 308. My first question is what is a 30cal. Then i got to looking at the different bullets. I found: 30 Cal .308 160 gr FTX® (308 Marlin Express) and 30 Cal .308 160 gr FTX® (30-30 Win) . I thought a 308 was a 308 but it seems that I thought wrong. BTW, first time that ever happened. So my second question is will and 308 cal bullet fit into any 308 case and eventually into any 308 rifle? Any help is much appreciated.