Just ordered my first 6.8 upper, a RRA Car w/16 inch barrel. I have 4 other AR15 platforms along with a 458 SOCOM on the way. The 6.8 has intrigued me since first reading about it a year ago. The guys in my shooting group have various shades of 6.8 and like them very much. Joined to get some tried loading data..I am interested in shooting 130 gr SP bullets but am afraid I have the wrong twist and barrel length, after reading some forum input..May have to drop to 115. Anyway glad to be aboard and do work at a small gunshop here in Aberdeen, NC so if you need help let me know...ElDee