Probably sounded like popcorn popping! Yeah...that Varget fills the cases. One of my pet loads in .223 was 27 grains of Varget with the Hornady 50 grain GMX. Looks like I'm not going to worry too much about 26 grains of 8028XBR. Might have to go buy a few more pounds of the stuff. After crunching, no pun intended, the numbers on those burn rates, it looks like 24.3 grains of 2460 is a starting load.