If you're looking for manga similar to Shin Big Magnum Kuroiwa-sensei, you might like these titles.
Sadao was a young man who did not have any hobbies and lived haphazardly. One day, he and his friend Shino accidentally stumbled into a shop… the airgun shop “Oono Workshop”. When they entered, they were greeted by the shop assistants, the sisters Mashiro Nabana and Lila. The girls caught their eyes, but moreso than that, they were drawn to the rows of guns lining the shelves which strongly tickled their boy’s heart. “So, if you guys are so fired up to shoot these things… how ‘bout you join us in the survival game tomorrow?” At Lila’s nonchalant invitation, they were made to join their first survival game!? They suited up according to Nabana’s lecture and rented a car… together with the Mashiro sisters, they made their way to the survival game field in Chiba. It was only later when they realized—Planning their journey there, running around the field here and there like children, and eating hot and spicy curry when they’re hungry. All those times will turn into their precious memories. That is the true value of the survival game!
Centers on Eda, the original manga's undercover CIA agent based in Roanapur's church, during her early days as a rookie in the CIA.