Ahh
After the shot was fired, Bruno no longer had a need of the pistol, so he decided to give it to the girl. Thankfully, Bruno didn't have to explain anything, because she already knew what he had in mind. To buy a better gun. That's obviously the thought that lay inside his mind.
An assault rifle. That is what he decided to buy, since it has a high accuracy, and also holds a lot of ammunition. One bullet per shot, is in fact the only thing that Bruno needed. That's because, his aim is precise. With a single shot, Bruno would hit the head of a zombie, and the zombies that stood behind it.
*Bam*
*Bam*
*Bam*
Bruno's trigger control was excellent, as every shot of his fired one bullet. The gun didn't have the option to switch the spray of bullets, obviously. Hence why, trigger control was of absolute necessity if he wanted to hit each head with one bullet.