updated by @rene: 09/07/18 07:20:32PM
And here is another possibility for you to consider. You felt no spirit attachment when this occurred which makes me believe that this is a past reflection of an event that took place years ago that happens on occasion because it is on a time loop of some kind. Our physical universe seems to have the ability to record events, especially violent ones, from the past. I believe that you were at the right place at the right time for this manifestation to occur.
You already know that the area you live in had a some what violent history so that would make sense to me. I think I asked before how old your house is and how much you know about its history but I don't remember what you said? Just curious, did the shotgun look like a new model or something from a time long since gone by, if you can remember?
You asked if this could be a psychic attack? Yes it could, but I doubt it, when ever your attacked either in our physical reality or the supernatural one there usually is no doubt as to whether it was an attack or not. I do however like what Cat Whisprerer said about having to accept isness, I imagine that part of our work here is to learn how to accept messages that are beyond our capability to understand them. If you can first accept something then usually you are setting yourself up, or perhaps open, is a better word, to let your own abilities to learn from and come to understand the very confusing world of spirit, or multi dimensions, as Peter says, with in your own little universe that is you!
I look at the universe like a school and you get to pick just how and why it all works the way it does. It's your choice alone to build what works for you. If you can believe, that, then all things are possible depending on how you, or I or anyone else, actually perceives these things. I suspect that our universe or multi-verse is much more complex than we can even start to imagine at this point. Enjoy the ride, we're far from finished yet! LOL