I'd stick with the ANS backblock. It looks great on the gun and is pretty small. A different bolt probably won't do much of anything for performance and most bolts won't fit the backblock since the pin goes through the top. The AKA Lightening bolt is the only bolt I know factory drilled for that type of backblock.
I think metalover or another machinist on CC made a 90* vertical ASA for the GenX5 too. He might be able to make you another.
Last edited by minimag03; 07-18-2013 at 11:20 PM.