I have done extensive research in 7,62x39 accuracy with shitload of ammo including hand loads. At the end of the day, it will depend on YOUR actual rifle. Here is an example. My friend just got a mini 30. so me, being a nice guy (LOL) gave him 7 types of ammo to try out, to see which shot the best
-123 gr Lapua FMJ
-154 Gr Wolf SP
-123 gr PPU Mil spec
-124 gr Wolf MC JHP
-Chinese yellow box steel core
-Federal AM Eagle 123 gr FMJ
-Winchester 123 gr FMJ.
right off the bat both Federal and Winchester shot terrible.
lapua came in second while Wolf 124 gr MC JHP shot a solid 1.4 inch group using 4x scope off the bench. ( this was used to evaluate all ammo)
everything else was about the same.
Now, in my Vepr K and SGL-21 Lapua shoots very well, while the same Wolf MC 124 gr JHP shoots ook. 3-5 moa.
at the end of the day, different rifles like different ammo (oh forgot, my 21 inch Rob Arm vepr shoots the 154 gr SP the best).
until you try diff ammo, you will never know which ammo is right for you
good luck!