Yes, I know it's a long shot, but what the heck, I'll try anyway. I have a SM40 that came with a BF-5 (for use on scopes < 500mm fl). I want to be able to use this on a scope with an fl of 600mm, so I need a BF-10. If you have a BF-10 and would consider a trade, please email details. I'll pay shipping both ways. Thanks for looking!