Forster Products' NATO Minimum rifle chamber gages will check to see that the rifle will accept the longest (headspace dimension) NATO ammunition cases that are currently manufactured. The Forster NATO Maximum rifle chamber gage checks to see that the rifle does not have excessive headspace, which could lead to dangerous pressure problems. Similarly, the 5.56 NATO caliber requires a slightly longer headspace than the commercial .223 caliber, which are commonly thought to be identical. For that reason, Forster Products is also offering 5.56 NATO Headspace Gages.
