Mc is a mega dipshit. Any sane person would realize when they are talking to themself. It was obvious from the first moment she showed up, yet she still didn't get it. She literally had to be TOLD that it was herself. Otherwise, this manga is good.
Time to act smug internet expert, achtually assuming it's modeled after beretta m9 it's probably is 15+1 in the chamber. Well could be, I dont know why you wouldnt load one more in the chamber if you are preparing to assassinate someone.
M9 has 15 round magazine, or well they also make 10 rounders, 13, 17, 18, 20 and 30 rounders.