My former next door neighbor was a great father, ex military, reasonably responsible son. He was careful with his BB gun.
The dad was auditioning new wives. One came and spent the weekends with her son. He had never had a BB gun and was infatuated with it. He shot it willy nilly and I have a holed window to prove it. The dad tried but was not vigilant continuously. The boy waited for the unwatched moment and grabbed up the gun.
My kids pretty much had access to the BB guns but I was a constant source of input both positive and negative. The real firearms were locked up in safes. Had one of them showed the slightest instability with their BB guns those guns would have also been locked up.