This is one of my favorite websites. You just enter the name of a movie into the search box - and you get a detailed rundown on all the firearms used in any given film. It even points out the errors, like using a WWII era machine gun in a SW. Admittedly, a lot of the more obscure SW’s aren’t represented, but there’s still a lot. I’ve pretty much run searches on every film I’ve ever seen.
Yes, I enjoy having a look through the IMFDb every now and again. Quite a few of the “bigger” spags are covered.