This is a pair of Go and No-Go headspace gauges, which have been ground to original 280 Ackley minimum specifications. They are recommended to ensure the proper headspace.

The 280 Ackley Improved Original gauges which are 0.004\"" shorter than 280 Remington gauges and now the new 280 Ackley Improved SAAMI gauges which are 0.014\"" shorter and compatible with factory cartridges. Be sure you know the needs of your project before renting.