They also measure displacement in ICE engines. You never see a 2 Quart muscle car (I'm guessing, I have nfi what a quart is)

And the druggies. Somehow, they had no trouble switching to metric.

We use it for drugs thank you very much.

Priorities.

Hey! HEY!

For many calibers, we often still call them by their size in inches.

All of these are named by the diameter of the bullet in inches.

eg: .22 means .22 inches.

-rim fire-

.17 hmr

(basically a .22 WMR necked down to .17. rising in popularity as a kind of... more powerful, faster thus flatter trajectory, replacement for longer ranged .22 shooters)

.22 short

(early revolver round, early semi auto round, still used fairly widely for both, today)

.22 long rifle

(still widely used today in carbines and revolvers, as well as down caliber'd variants or kits for 'meaner' looking semi-autos)

.22 WMR

(.22 lr, but magnum. big boy .22)

-center fire-

.223

(the 5.56 before the 5.56 was NATO standardized. very short summary: they basically just put more gunpowder in a .223, and called that 5.56x45. many in the US still use weapons that are made for .223... but you're gonna want to upgrade your barrel to something that can handle the greater gun powder in 5.56 if you are not a fan of your gun exploding in your face when you fire it)

.38

(many variants of this exist, most notably the .38 ACP for semi autos, and the .38 special for revolvers)

.40, or 'forty cal'

(early attempt at making something meaner than a 9x19mm, led by the FBI, less generally popular today, but was very popular with the FBI for a while)

.45 ACP

(the caliber of the iconic Colt 1911)

.300 blackout

(an 'intermediary' round that is between the NATO 5.56 and 7.62, often used with suppressed weapons)

.357 magnum

(very, very common revolver round. Sig Sauer actually at one point made a .357 sig for use in semi autos... don't think anyone really uses those any more)

30-30, or 'thirty thirty'

(lever action carbine round, been around for over 100 years, like the .357, probably not going away anytime soon, as the lever actions that shoot them have not only remained fairly popular, but also are currently having a bit of a rennaissance with many gun makers in more legally restrictive states offering 'tactical' lever actions with modern housing, collapsable stocks, optics mounts etc)

30.06, or 'thirty ought six'

(basically, a 7.62 NATO that's 12 mm longer, used to be standard in military springfield rifles, also used in the BAR, still used by many hunters today in some kind of rifle)

.338 Lapua Magnum

(specialized sniper rifle round... if you don't count 50 BMG or even larger, anti-materiel rounds, the lapua has the longest recorded, confirmed sniper kill in history... though this may possibly now be incorrect as of the RussoUkraine conflict... point is, its a very capable sniper cartridge, good deal of wealthier US hunters and long range target shooting enthusiasts love it as well)

.410

(for some estoeric reason, this skinnier shotgun round is not referred to with the standard 'gauge' nomenclature)

.44 magnum

(dirty harry's revolver caliber, which will take your head clean off, assuming you do not feel lucky)

45-70

(older, fuck off huge revolver / lever action round)

'50 cal'

(can refer to either the .50 AE, famously used in the Desert Eagle, or the .50 BMG, used in the 'Ma Deuce' M2 Browning Heavy Machine Gun, and the Barret M82 Anti Materiel Rifle)

...

I've almost certainly missed a good number, point being, us American gun nuts... and/or gun nerds... yeah we learned metric, but we still use inches/imperial all the damn time.

We really only call NATO standardized rounds by mm. 9mm, 5.56mm, 7.62mm... and I guess the 6.8 grendel, and newer 6.8x51mm round the Sig Spear / M7 uses... and also I guess we size grenade launcher rounds in mm, but uh, ....civillians generally don't get live grenade launcher rounds in the US.

We had to draw the line somewhere rofl, and apparently it is grenade launchers, hahahah.

M'erican here. My workshop is 100% metric. I do far too much measuring, designing and planning to fuck around with inches, feet and football fields. Motherfuck the imperial system. America has been robbed of the superior until of measurement. Every last bit of my work is in millimeters and it will be that way until I die in a horrible firey accident in my shop because beer and dangerous power tools are just too much fun when taken together.

How dare you!

We also measure our drugs that way

The imperial system makes you a worse shot. Everybody in American stories misses by inches. In European stories, they miss by millimeters. It's quite the difference: 25 times worse.

This is why i use the amertric system

It 318 kft not 60 mi or 100 km. That avalanche was 1 decaempire State building in volume. 1 mi is actually 2.28 kft.

Hey, we use grams and kilos for...other things too.

It is funny how we're schizophrenic about it, though. Things will go from grams to ounces and then to kilos...or, so I've heard.

Edit: American cars are also kind of schizo like that, or at least they used to be. The engine and everything attached to it was metric and everything else was SAE. Fun times.

Longtime woodworker here (American). Fractions of an inch have always been a pain. Finished lumber like 2x4s and 1x12s have never in my lifetime been the size they're known as, but that's a matter of subtracting halves and quarters of an inch and everybody was used to it. Then maybe 20 years ago (no need to correct me, it really doesn't matter) companies decided that instead of making plywood the thickness they said it was, they would subtract 1/32th of an inch, because hey less wood means more profits! So for example a sheet of so-called 3/4" plywood is only 23/32" thick. Similarly with half-inch, etc. This means a slot cut with a 3/4" router bit, which used to fit a 3/4" thick shelf, is just slightly loose now, and if you are stacking multiple thicknesses the slight inaccuracies compound themselves. What the Actual Fuck. I have a metric tape measure, which makes some figuring easier, but inches and fractions of inches don't convert to exact mm. The imperial system is a shit show.

And the only time they use the proper date format is their national holiday.

Oh no, it's worse than that... we use the metric system to measure the customary system...

The Mendenhall Order marked a decision to change the fundamental standards of length and mass of the United States from the customary standards based on those of England to metric standards. It was issued on April 5, 1893, by Thomas Corwin Mendenhall.
[...]
Mendenhall ordered that the standards used for the most accurate length and mass comparison change from certain yard and pound objects to certain meter and kilogram objects, but did not require anyone outside of the Office of Weights and Measures to change from the customary units to the metric system.

https://en.wikipedia.org/wiki/Mendenhall_Order

Technically every unit in the US customary measurement system is just a weird conversion factor of an equivalent metric unit. At this point 1 yard was defined as 3600/3937 meter, which means 1 inch = 2.54000508 cm. By 1959 everyone finally agreed that this was stupid and redefined it as 1 yard = 0.9144 m (1 inch = 2.54 cm).

All measurements in the US are based on standard reference objects provided by BIPM.

Hey, we also measure our large soda bottles that way!

Most of us know what two liters of carbonated sugar water looks like.