I was curious about this new, 40#, sinew backed juniper I just finished. So I ordered a cheapo Chrono off Amazon and tried it out. I'm shooting 750 grain arrows, keep in mind.
My favorite hunting bow, a 57#@27" hickory flat bow, was hitting 137 fps. The 40# sinew backed was shooting those heavies around 120-125. I've been reading that a lot of people are achieving 180 fps or more with a self bow, but with arrows that are a lot lighter, and probably with bows that are designed to be fast rather than to be able to hold up banging around in the rocks and timber.
I figured if the lighter bow was as fast as the heavy, I'd hunt with it, but I'm reluctant to go any slower than I already am.
Thoughts? It isn't something I'm too worried about. Just kind of interesting.