The Picard ManeuverWait, not like that
alcoholicornMetric 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.
strawberrythen why is it called 556 if its actually 5.7?
556 was the measure of the inner diameter of the rifling of a barrel of a gun that shot 556.
It’s confusing. That’s why for most shotguns, we measure the width by the number of spheres of that diameter that would equal one lb, eg a 12 ga shotgun is the diameter of a 1/12lb sphere of lead.
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.
That’s actually fascinating. Thank you.
No problem. There’s always a reason, and usually a pretty interesting one, for old odd hold overs like this, but it’s been 200 years since shot towers were a thing, only history buffs and muzzleloader enthusiasts really know about these.