AKs are hard to accurize. As was mentioned, they just weren't designed for that. For 308, I recommend a Molot VEPR. They are built a little heavier and they are nice guns. I had a 308 Super VEPR back in the day that was a really nice rifle. It had the long barrel, 23" or something like that.
While it functioned flawlessly, it was heavy and a chore to wield. Best group I ever got was 2" off a bench, sandbagged, with FGMM in 168, 175. Tried everything from handloads to the best factory match. 2" was the best and 2.5" - 3" was more common. It just wasn't made to be a precision rifle though it was made to look like one.
Anyways, if it were me, I would find a 308 VEPR. You may get one that shoots better, you never know. Thing is by the time you drop the coin for the VEPR you could build a big block AR that shoots circles around it.
I like AKs, I have 2 I built myself from kits. They serve their purpose. But I wouldn't trade my large frame AR for 2 VEPRs in 308. I love it, it shoots amazing, it handles amazing, it's my favorite rifle.
As far as a 9mm AK, there are a couple models out there now that take glock mags in 9mm. There again, I think the AR platform is better if your gonna be shooting a lot. My AKs are 7.62x39 and 223. They are beaters and I've shot them a lot. But they don't get much play anymore, I just have them to have them. I go to my ARs for everything, but that's my preference.
