I said no to rams and rcs because I have had a lot of experiences with both and it's just never worked out. In fact, most fish don't work out if the end goal is to have a breeding/growing population of RCS. If you don't care about losing the shrimp then give it a shot, some people do matchups like this with their extra shrimp (when a tank becomes overpopulated), and who knows, it might work out.
Just like with feeder fish and a big cichlid, if you keep him well fed he might leave them alone for days, or weeks, but it's only a matter of time. It could be made to work, but it's asking them to go outside of their nature to do so.