Been having the same issue for months with a 308 conversion. Your problem is that the case is hitting the front corner of the pistol grip assembly right under the ejector plate. Take out your main spring and replace butt, remove cover and tray, insert pulled bullet piece of brass into chamber and force bolt forward so it grabs the round. With a quick jerk of the cocking handle you should be able to replicate the failure. Now remove the pistol and sear assembly, repeat procedure and the brass will be ejected straight down instead of forward. Will post more when a mod fix is created.
