I tried and tried to get the 100 gr TTSX to shoot in my bee, but after burning 3 different powders and trying various seating depths the first time I tried the NAB I was shooting 3/4". BTW, the Bear I shot was at close range and I probably hit him around 3350 fps. No blow up either. I think the NAB is a perfect cup/core bullet for the .257 not to mention the high BC. Think of it as a bonded partition per Mule Deer.
