The 5.56 NATO chamber has a .125” longer throat...
Yeah...cartridge dimensions are the same, as I posted. Powder charges and chamber dimensions vary. There may be about a 1% difference in case capacity, due to thicker brass used in 5.56.
27 posted on 01/30/2024 1:56:52 PM PST by gundog
( It was a bright cold day in April, and the clocks were striking thirteen. )