I’ll be using MK 318 and MK 262.
M193 and M855 is for practice.
It depends on where you live. I live in the suburbs. I don't plan on any 300+yd shots. If I'm that far away from some targets, they don't even know that I exist, so why call attention to myself. In a SHTF situation, the fewer gun battles you get in, the better. I'm well familiar with longer range shooting since one year in the NTIT, I had 20 hits at 500yds. Not great, but not bad.
