Two years ago I switched my .280 from 160 grain NP to 140 grain TTSX, couldn't be happier with the results. The 4 deer I have taken in that time have all died very quickly, 2 mule deer dropped on the spot, 1 whitetail taken on the run managed about 3 steps and one other mule deer managed about 5 steps. Meat loss was very minimal. These deer are not the large-bodied deer that you can get in Saskatchewan but I can't imagine the results would be much different given the same shot placement. I am thinking that 120 grain TTSX might work just as well.
