How did you luck out? You have not tried high brass yet and the LRBHO does not work because the SGM mag follower sit's lower then the factory mag. My friends vepr did this also, you need to remove the LRBHO lever and bend it down some. My SGM mags feed low brass 100% no ftf.
Oops, must have deleted the part where I said that my 10rder works with high brass. After reading this thread I loaded up my 10rder with buck and it feeds that first round every time. I am using 2 3/4" Remington Express 00 buck IIRC.