I think I have finally found the min speed this year. I tore my rotator cuff and shot a turkey at 10 yards with a 35lb osage selfbow. This bow shoots about 140fps with 450gr arrow. I hit this turkey in the back and it didn't penetrate all the way but broke his back. I sure wouldn't shoot this combo at deer.

I am not ready to shoot my 50lb-55lb osage yet but hope to be by hunting season.