Accuracy is far superior then any AK based rifle.
AKs are crude and sloppy. The AR-15 platform is a vastly better rifle all the way around.
On average an AR is more reliable than people give it credit for, and the AK is more accurate that people give it credit for. I have certainly seen AR's that would only shoot 3-5 MOA, and I personally owned an AK74 that would do 2-3 MOA with surplus ammo. Luck of the draw. On average an AR shooting average ammo, will have an edge over the average AK shooting average ammo, in accuracy probably. A lot of that is that average AK ammo is less inherently accurate than AR ammo. The AR platform has some things going for it, as does the AK. In certain aspects is the AR better, yes, but in certain areas the AK has advantages over the AR.
To get to the OP's question, however disjointed things may be up to this point:
A 7.62x51 NATO/.308 winchester AK is a specialty item, that to my knowledge has never been produced as a military arm. The closest I know of is an 8mm AK, produced as the Zastava M76, in Yugoslavia. These were basically designated marksman's rifles, and work well for that. A friend has one, it's pretty much an upscaled AR, sort of like the AR10 vs AR15 (I know the AR15 is a scaled down AR10). 8mm Mauser hits with authority just as well as 7.62x51/.308 does.
If you're not committed to the AK platform, there are plenty of 7.62x51/.308 rifles out there that are not AR based. The big 2 options are the G3 and FAL.
The H&K G3 is still in active duty with a couple of militaries, and the civilian version is the HK91. Mags used to be dirt cheap, no clue on them now, I haven't looked in years. Ergonomics on the G3 aren't great, just like most H&K products, but they do run well and shoot well.
The FN FAL is also still in active duty with a couple of militaries. Multiple companies sell rifles made either from kits, and DSA makes a complete rifle on new receivers. Mags are reasonable in price, and the ergonomics are a bit better than the G3. You can get an FAL in everything from super shorties with rails everywhere, to the original 21" fixed stock iron sight rifle.
There are plenty of other 7.62/.308 battle rifles out there like the Beretta BM59, CETME, etc.
I wouldn't discount the smaller calibers like 7.62x39, 5.45x39, 5.56x45, etc. All of them work quite well for self defense purposes, and I will give the 5.56x45 the nod for having probably the best ammo options out there. Speer Gold Dot is superlative for SD/HD purposes, and is extremely accurate as well. Hornady TAP would be my second choice, and is also an excellent round. In .308 pretty much the exact same two recommendations. In 7.62x39 and 5.45x39 I am not aware of anyone producing a round specifically for SD/HD. Hornady does make pretty good hunting rounds in those calibers, but they are not purpose designed SD/HD rounds. Accuracy in my experience is excellent if your rifle likes them.