It seems that all ammo is scarce except maybe pistol ammo.I have been bouncinjg around between caravans, Krasnoznamenny, and Ortanoa (?) collecting ammo and have about 30 rounds of 7.62. That amount is negligible for an assault rifle. Fortunately I have a high speechcraft so I can skip many encounters but neither do I get any experience. I thought guns would be the key to winning this game but without ammo it is hopeless. Maybe I should have created a melee character- at least I would not have to worry about ammo. Last time I got 7.62 from that crook in Krasnoznamenny he only had 3 rounds for sale. Really gets boring walking all over looking for bullets. Is this what all of you do to win the game?
Personally I think it's great that ammo is scarce in this game. Having said that, you will eventually reach a point in the game where ammo isn't really a problem any more.
What I did is temporarily switch to different weapons where I still had lots of ammo, which usually meant going back to slightly weaker weapons.
Also, I built my main character to be rifle-centric, so I tended to primarily use aimed shots at the eyes. I also didn't give the other characters auto weapons until relatively later, since I didn't want them to spray me with bullets. So that's probably the main reason I had tons of ammo by the end.
Note even if you built your PC around using auto weapons, unless you're using LMGs you can still do aimed shots, which are often more effective (and of course use less ammo). You don't need a really high weapons skill to get reliable eye-shot criticals either, and head-shots are even easier (though not as likely to crit from what I can tell).