One of the most critical parts of a rifle's accuracy potential is the throat cut in the barrel. It must be concentric to the bore. I have a process, tooling, and attention to detail that ensures this every time, no matter how short or long the cartridge. I dial to less than .0001" with direct measurements, no pins, rods, or other gadgets. The farther into the barrel, the more difficult and critical this becomes. Below is a 30 XC chamber. That throat is roughly 3.4" inside the barrel.