I measured the wieghts of .308 150gr bullets. Out of 10 of them I got deviations from 145gr to 155gr. Thats huge. I did the same with Sierra Gamekings. Deviations of 2gr max. I then measured the OAL of 20 shells of factory loaded coreloks. Deviation from 3.53" to 3.59" . Thats also pretty huge. I don' t know. I will have to see it again to make sure. This FN Tactical has a barrel that is huge. The gun wieghs over 12lbs. With this bull barrel, vibrations and finickness should be at a minimum with a gun like this.