556 was the measure of the inner diameter of the rifling of a barrel of a gun that shot 556.
Metric is confusing. That’s why for most shotguns, we measure the width by the number of lead spheres of that diameter that would equal one lb, eg a 12 gauge shotgun is the diameter of a 1/12lb sphere of lead.
Nobody knows how big 18.53 mm is, but everyone knows what a 12 gauge shell looks like.
Oh, and gun powder is measured in grains, maybe early smokeless pellets were about the same size as grains of wheat.
he’s serious. The old casting method for round shot was to dump a measured amount of molten lead from a tower into a pool of water 40 feet below. the molten lead would form a sphere in free fall and fully set in the water, so it was convenient to define gauge diameter by fractional weight of a pound. Twelfth pound sphere fits a 12 gauge gun, etc.
The problem is it’s impossible to tell whether you’re joking or being serious. Throwing molten metal off the tower sounds like the most ridiculous thing ever, but apparently is a real thing.
Metric was too confusing for bullets, so we use both, and but neither of them are actually the diameter of the bullet, most of the time.
.223" is the same diameter as 5.56mm (which is 5.7mm across), but if you use 5.56 in a 223, it might kill you.
223 in 556 is fine, might fail to cycle.
then why is it called 556 if its actually 5.7?
Maybe the original was 5.56mm and some dumbass decide “nah, not enough b u l l e t, better make it 5.7mm.”
556 was the measure of the inner diameter of the rifling of a barrel of a gun that shot 556.
Metric is confusing. That’s why for most shotguns, we measure the width by the number of lead spheres of that diameter that would equal one lb, eg a 12 gauge shotgun is the diameter of a 1/12lb sphere of lead.
Nobody knows how big 18.53 mm is, but everyone knows what a 12 gauge shell looks like.
Oh, and gun powder is measured in grains, maybe early smokeless pellets were about the same size as grains of wheat.
The problem is it’s impossible to tell whether you’re joking or being serious
he’s serious. The old casting method for round shot was to dump a measured amount of molten lead from a tower into a pool of water 40 feet below. the molten lead would form a sphere in free fall and fully set in the water, so it was convenient to define gauge diameter by fractional weight of a pound. Twelfth pound sphere fits a 12 gauge gun, etc.
The problem is it’s impossible to tell whether you’re joking or being serious. Throwing molten metal off the tower sounds like the most ridiculous thing ever, but apparently is a real thing.
Mostly.