I just posted this in a thing about military chic, but now I'm posting it here because I am. Deal with it if that bothers you (this site is free, you can always just leave or unfollow me). For people who want a military chic look made from actual military stuff, some tips from an ex military surplus store worker and briefly online seller...
I recommend the Swiss wool coat highly with one caveat. It looks a little...German, but it's amazing quality (because the Swiss believe in quality), and if you go for one of the slash-pocketed ones they are just gorgeous (the older horizontal pockets are fine too). It comes in long and short varieties, and the rolled French cuffs are handy if your arms are a bit longer. It's a lighter weight wool coat, good for up to 45F and down to about 20F, colder with a sweater. I recommend the older ones with metal buttons, but there's a later plastic/bakelite button version that works well enough too. They make corresponding trousers that are great, but at that point you are going in almost full uniform, so I recommend switching it up with a good pair of Swedish or German (postwar) wool trousers just so you don't look too much like a certain type of 'German history enthusiast.'
Here's a link to one on eBay. They tend to run about $70-$150, plus shipping, so watch where you order them from because if you're getting something from Lithuania, shipping's going to be a bit. To defunkify anything (and there will be funk most probably), I recommend handwashing or soaking that shit in a mild detergent or Woolite.
However... Don't sleep on Bulgarian Army surplus. Their wool greatcoats are made on the Russian/Soviet WWI/WWII pattern, single breasted and slightly offset. Middle weight, with enough room for a sweater depending on what size you order relative to your build. Plus, there's usually an inner pocket for your trusty Makarov while you hunt for enemies of the Revolution or whatever. Again, it's got the French cuffs, and those are just lovely.
Or you have your US Army greatcoat. A beast, but wonderfully warm:
And then there's the US Marine WWII wool coat. This one is a steal at $48, but you'll have to be small enough to fit into it.
It's what I would call a forest green, darker than the mustard-green color of the US Army coat, and the wool is less coarse, this is a coat you could live in, especially if it still has the silk lining. It's thick enough, but not so thick you can't move around in it (that's true for all the coats listed here). You can get it (and the US Army greatcoat) in a cutdown, jeep coat style. It's shorter and made for, as you guessed, hopping in and out of a jeep without getting snagged on anything so you can go send whatever fascists you need to to their reward. Nice, but you'll want a good pair of trousers with it (again, check out the USMC wool trousers from this era, they're handy). The quality on this is second only to the Swiss stuff. I'm not sure why. If you're looking for something in the same color but a bit lighter and shorter, I recommend the winter service jacket above.. And we've got the British Household Guard overcoat. Technically fine, but, eh, I'm not a fan for some reason. Well made though.
I'm more partial to this double-breasted British coat. And this Civil Defense coat is just a fucking gem. I'd love to find one in my freakishly tall size.
Avoid, I'd say, the later Cold War era Soviet Coats, they are big and wool and tempting, but they are usually stiff as a frozen poet in the gulag. I've owned two (bought cheaply each time) and given them away because they just weren't keeping.
Just...I get it, I get why it's tempting. It's got that Soviet swagger, but like the later Soviet Union, inside it just doesn't quite work.
