Lyman's ammo checker allows reloaders to quickly confirm ammo will fit in a firearm's chamber. Drop loaded rounds in the ammo checker and if it fits the gauge, it will fit the gun's chamber. Machined from a solid block of 6061 T6 aircraft grade aluminum and cut with custom tooling to SAAMI minimum chamber dimensions, then bright orange anodized to make it easy to find. One gauge will work with a variety of calibers, and each caliber is clearly engraved on the gauge. The Large Rifle Gauge will check 243 Winchester, 270 Winchester, 30-30 Winchester, 308 Winchester, 30-06 Springfield, 300 Winchester Short Magnum.