When to comes to using props that are hard to come by cheap, such as guns, for example, you can always get fake guns, but some of them don't look real enough. The bigger the gun especially, the more you can tell it's a prop. The obvious solution would be to add blur, in post to mask it out, but how much blur is the filmmaker allowed before it looks TOO BAD? I can't think of any movies I've seen where it was very noticeable to compare it too.