The Romans were really good at philosophy, the arts, and military conquest. But their math sucks.
If my country was one of the last metric hold outs in the world, I wouldn't cast stones in this direction.
:P
C'mon, be fair. Most Americans can't do math in Imperial measurements either. We don't convert because then no one else can figure out we're inumerate, which is illiterate only with numbers.
Americans use metric for a ton of super-American stuff! Bullets. Soda bottles. Nutrition labels*. Hard liquor. Oreo serving size. Illegal drugs. Bombs. Protein power. Liquid limits for airport security theater. Electric metering for all our stupid devices.
*The calorie is an SI-based unit, though in fairness we print it as "cal" instead of the more accurate Kcal.
'Mericans use 7.62x39mm and 7.62x51mm as very separate things.
https://en.wikipedia.org/wiki/7.62%C3%9739mm ie COMMIE and worse... vs
https://en.wikipedia.org/wiki/7.62%C3%9751mm_NATO .... who hooooh
7.62x51mm is a smaller packaging of the 30-06 beloved by 'Mericans.
I recently overheard a bar discussion about the unavailability of 9mm and 5.56mm ammo. so even 'Mericans get some of the metric system, even if not in a otherwise socially acceptable way.
I noted in the bar discussion that I heard _no_ mention of imperial/US units.
For those interested in such discussions I recommend :
https://www.youtube.com/c/ForgottenWeapons/videosI'm amused about the number of non-US persons checking out the gun porn, complete with Gun Jesus.
No I'm not kidding. Just to be clear, he IS kidding and slightly shy about it , just like Brian.
https://www.hkpro.com/threads/hk-gun-jesus-poster.491582/ although if you are a French gun, you do get a pass to Heaven :-), as he has written a book on the subject.