Rate of fire........Bartlein carbon. Had one that was good. Most recent thats junk. Know myself and 3 other guys that have sent 22,6mm ans 65s back in last 3 months. Mine was a 6gt, first 8-10 rounds would walk 2" right, and then stack into tiny groups hot barrel. Did it with 3 different proven loads from my other gt's, I have 5. I alternated the heat up loads, and by the time the barrel got "too hot" it finally start shooting, all 3 loads into sub half moa. Bartlein says they haven't even looked at the barrel, too busy with Isreal/Ukraine stuff. Guess there are too many us troops shooting custom bolt guns headed to fight right now for them to QC any of these 4 barrels. We're all pretty ****ed. I for one will never buy another Bartlein anything after this.