You have to have a fast closing trap for reds, they’re that fast! My favorite trap, link below, has a rather unique feature where the door of the trap is recessed. This has been handy for a lot of reasons. I made a sliding 1/4″ mesh door that has a golf ball size hole in it to block out greys but yet allow the smaller reds access to the peanut/peanut butter bait in the trap area.
http://www.safeguardproducts.com/wp-content/uploads/95-006_UniversalTrap.pdf
So far no joy The last red that was around was “trap smart” and required a pellet. The current count is eight. May try a solid door with the same size hole instead of the wire to make the access hole more obvious.