Redding Neck Sizing Bushings are offered in two styles, both with identical external dimensions of 1/2 inches O.D. x 3/8 inches long, ensuring they freely interchange in all Redding Bushing Style Sizing Dies. Comes in .001 inches size increments, they cover the full range from .185 inches to .368 inches, accommodating calibers from .17 to .338. Each bushing is clearly marked with its size I.D. to simplify selection. By choosing the correct bushing, you can achieve the perfect neck tension, ensuring the bullet is held securely without excessive resizing, allowing for optimal ammunition performance and consistency.