I’m not a lawyer and this is not legal advice. It doesn’t matter. If anyone points an object that looks like a gun at you, you have the right to respond with deadly force to stop the threat. Unless a prosecutor can prove that you had knowledge that the object was a BB gun, or some other less than lethal object, then you there is legal standing for your actions in self-defense.
BB guns and airsoft guns are so realistic that I use them in the classroom to demonstrate that unless you have time to closely observe the object you can not tell the difference. I lay a Smith & Wesson M&P 9 and a Umarex M&P next to each other and give the students 15 seconds to look at them and tell me which is the BB gun. From two feet away with that much time some students can pick out the CNC slide verses the molded slide or notice the 9mm hole in the muzzle verses the .177″ retracing barrel.
They have all been impressed with the similarity and agree that they would not be able to tell the difference if someone was pointing one at them. I think that is a valuable lesson to be demonstrated before a person is faced with the scenario because of the physiological effect of the aftermath of shooting someone who had a BB gun versus a real gun. You have to understand that the perpetrators intent is the same. To intimidate you into submission.
By presenting a gun, or something that can not be distinguished from a gun during a confrontation the attacker is demonstrating the intent to use deadly force against you.
Take a stroll down the BB gun aisle at you local Walmart or sporting goods store and see for yourself how realistic these BB guns are. Prepare yourself and don’t feel sorry for BB gun wielding bad guys when they get shot in response to their poor decisions.