My bear was a bore that was estimated at 2.5 years old. It was by itself with and it was definitely the one making the noise. I followed him for 100-150 yards before I could get a good view and shot. I am not sure it was the same "popping" you guys are discribing. I obviously don't know for sure, but it sounded like my GWP "whoofing" (1/4 bark) at something. Never sounded pissed off, but I don't know how I would tell anyway. He did this right after he winded me so very possible it was a warning. Right after that he just walked away.