Chapter 5. When Dally visits the boys after five days,what was the reason for him carrying a gun?

Dally is carrying a gun because of the gang war that has excalated since Bob's death. He does, however, say that it isn't loaded, and that it's meant as a bluff.

"Don't worry," Dally went on, "it ain't loaded. I ain't aimin' to get picked up for murder. But it sure does help a bluff. Tim Shepard's gang and our outfit are havin' it out with the Socs tomorrow night at the vacant lot.