When I test my game in studio, I notice that as time goes on my FPS progressively gowns down, to as low as even 8FPS. I have no idea what is happening? What's the best way to track down what is making FPS so low? Also, my game isn't really structurally complicated. Just some parts and a few CSG unions.
Fighting Lag, Rbx Wiki
Those were all the helpful links I could find. However, a problem you're probably having is with the bullets not being destroyed or runaway loops.
Good Luck!