The case is both shorter and narrower than 556/223, so it won’t even sit right in anything not designed for it. But FN makes quite a few guns that use it.
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 gauge shotgun is the diameter of a 1/12lb sphere of lead.
Grains as a measure of weight comes from the Troy weight system, think Troy ounce of gold. It is a very old system that for a long time was mostly used by apothecaries and probably has its origins in Ancient Rome.
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.
Here’s where it gets political. I learned about shot towers in passing years ago and thought that was a good idea. You learned about shot towers in passing, but then with a detailed explanation, still thought that was ridiculous. One of us is prone to rational thought and the other is not. This is a 17th century conversation happening now.
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.”
OK, so there is a 5.7mm, that’s the same diameter as 5.56/.223, but it’s not compatible with either because of the french.
Is it a special round? For example, the cz 75 uses special 9×19mm parabellum or 9x21mm.
Kinda?
The case is both shorter and narrower than 556/223, so it won’t even sit right in anything not designed for it. But FN makes quite a few guns that use it.
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 gauge shotgun is the diameter of a 1/12lb sphere of lead.
Grains as a measure of weight comes from the Troy weight system, think Troy ounce of gold. It is a very old system that for a long time was mostly used by apothecaries and probably has its origins in Ancient Rome.
The problem is it’s impossible to tell whether you’re joking or being serious
Mostly.
He’s correct and showing the…quirks of the system.
say it ain’t so!
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.
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.
Here’s where it gets political. I learned about shot towers in passing years ago and thought that was a good idea. You learned about shot towers in passing, but then with a detailed explanation, still thought that was ridiculous. One of us is prone to rational thought and the other is not. This is a 17th century conversation happening now.
Ah no, it’s just that from reading this, I imagined it being poured outside, not inside the tower.
Like, someone looking at Galileo doing his experiments dropping weights off Pisa tower, and saying:
— What if we put a bucket underneath? What a splash it’d make!
And another one going:
— Yeah! And why just weights, let’s throw molten lead off! What safety concerns? Haven’t heard any