Made specifically for .243 diameter, this Forster Outside Neck Turner Pilot #243 is an exceptional buy for someone who does home reloading. To ensure accuracy when firing, a bullet must have the same neck thickness. In order to expand properly and avoid a bullet-to-bore misalignment, this pilot creates wall thickness of the same size. A goal of reloading is to have consistency in your ammunition, and with this pilot, that is made possible. The mandrels are evenly ground to 0.002 to 0.0025 inches smaller than the diameter of the bullet, which boosts performance.