I don't like the barrel shadowing ether but I tried everything that Stranger danger said and with AVA along with other guys on this form and I love it.. I don't any problems with my M4 im really happy with it i can say this with all the improvements that i made to the shotgun she's up to 99.9%half dam near perfect... at this point i can't think of anything else to add to the shotgun. soon i will be sending all my guns to Robar Guns and I'll report back with pic once they are done if anyone is looking to do same job as im going to do.thanks to Stranger Danger and AVA and Taran TacticalInnovations for all the hard work that these guys do here for they make it all possible.