Isekai Shokan Ojisan No Ju Muso Life Sabage Suki Salary Man Ha Kaisha Owari Ni Isekai He Chokuki Suru

Synopsis:

The moderately aged man and airsoft lover Daisuke Koga is called to an alternate world on his 40th birthday celebration. Daisuke must travel between the real world and the fantasy world to save the other world because he can turn airsoft guns into real guns. Daisuke, along with Rena, the female swordsman, becomes the only gun user and takes over the fantasy world after work!