I got my MCARBO tube sleeve, RDB, and QD Sling Mount today and installed in less that 30 minutes with the help of your videos. I have a extended slide release and muzzle break on the way from you guys. Thanks so much for these nice little upgrades that you offer and the great customer service. I am also considering the MCARBO optic mount and trigger job for the future. Take care, MCARBO brotherhood.