So, I am an aspiring filmmaker, and I am in the process of planning a short film that I want to take place in a field that is not mine, and I was planning on using a prop gun. I have been told that if you are going to use prop guns, you should let the police know ahead of time, but that brings up another issue: I don't have a permit. The field that I want to film in is in a nature park, so it's not private property, but I don't actually have the money to apply for a permit. There's really no information on how to go about any of these steps I should be taking, so I am asking you guys! I am based in Portland OR, and have a budget of nothing. Thanks for any feedback!