In September, 1998, Kendo's inventory was emptied out to civilians during the outbreak, leaving very little behind for remaining survivors to pick through.
Reports differ as to how events transpired; in some accounts, Claire Redfield, a college student looking for her brother or rookie officer Leon S. Kennedy were able the shop after their car crash. After a misunderstaning amidst the confusing situation, Kendo decided to help and locked the door. But after that, zombies broke into the store smashing the front window grabbing Kendo in the process. 
In another account, Robert hid in the store from the zombies, along with his wife and daughter Emma, who were later infected in the process. When her wife succumbed the infection, Kendo killed her to protect himself and his daughter from the threat she had become. Eventually, around the night 28 September, he encountered Jill Valentine inside his shop before leaving without him. On September 29, rookie officer Leon S. Kennedy and agent Ada Wong passed through the shop which led Robert to confront them as trespassers. After the meeting, he was forced to kill his daughter before committing suicide.
Gun Shop front seen in the Resident Evil 3 remake.
In the original Resident Evil 2, the zombies broke into the store smashing the front window after Kendo helped the survivors he met. However, in Resident Evil: The Darkside Chronicles, the zombies broke into the store without breaking the front window before Leon and Claire arrived.
The gun shop appears in the demo of Resident Evil: Operation Raccoon City but is inaccessible. In an interview, producer Mike Jones hinted at the possibility of exploring the shop and finding weapons. However, this feature was never implemented in the final release.