Sounds like you already know why it's happening. If you can't keep it on then it's got to go. I don't think the smaller one will help.

I might try putting a 1/4" deep hole the size of the arrow where it sits to see if that would do it, but that's just me (if I couldn't sell it or use it). Or maybe add something to it like glue some small pieces of teflon to keep it in place.