High heat treatment steel bushing for the recalibration of the collar.
These bushings are hand polished with a hardened surface of RC 60-62 to reduce calibration efforts. Available sizes are calculated in 0.001 inch increments.
Dimensions: 1/2 ″ OD x 3/8 ″ long
Good collar tension is now recognized with a value of .002 or .003 lower than that of the finished cartridge, but there are two different measurement methods to choose the bushing that best suits your needs:
PAY ATTENTION: all measurements and measurements (as well as the diameter of the bushing) are in thousandths of an inch.
- measure the thickness of the collar (e.g. .015)
- multiply this thickness by two (.015 × 2 = .030)
- add the diameter of the ball (e.g. .308 + .030 = .338)
- subtract .002 or .003 (depending on whether you use moly or Hbn coated balls) from the total and order the bushing with that number.

Redding Bushing Steel .310