Cumberland County Coroner Gary White told the Lexington Herald-Leader the family had not realized a shell was left inside the gun. The boy picked up the gun from where it was kept in the corner of the house and it accidentally fired when he began playing with it.
The siblings' mother was home when the shot was fired. The toddler was rushed to Cumberland County Hospital but pronounced dead.
"It's a Crickett," White said. "It's a little rifle for a kid. ...The little boy's used to shooting the little gun."
The boy's gun, given to him last year, was a Crickett Firearms model made by Keystone Sporting Arms and branded as "My First Rifle." The weapon appears in a variety of vibrant kid-friendly colors and designs, and the company website says the rifle aims to "instill safety in the minds of youth shooters."
White said the shooting will be ruled accidental. "Just one of those crazy accidents," he said.