Don't have any first hand knowledge but have done alot of research lately. Have spoke to BM Ag. as John W suggested. Go back a few topics and a page back or so and find grass talk. There are a couple real good experts there. I would ask you conditions of helicals and bars ect.IJ All forward bars, third helical extended over feeder, steep pitch barsIJ, extended cylinder bars to discharge at least,. Blue grass seems to be one of the hardest grasses to get right. Are you giving it a try when crop still has enough moistureIJ Did you blank off every opening in concave and grate or every other or whatIJ Maybe block off more. We used to have to block off cage at seperator side with hard panels or bailer belting ect. for a couple crops before we got P3s to flow straw that likes to break up better. I'll be giving the Bluegrass a try for the first time shortly and will be ready to install rotor sweeps if overthreshing. Removing some bars on seperator side may reduce thresh also!!!! let me know what you have and how your doing. There was a grass expert asking about a chaffer earlier here and he has the Bluegrass fairly under control I think. He is in the BM ag. area and maybe he can add something here. Good luck.