I think my V-1 2010 23" Vepr is a 1:12.6R Twist. 147gr seems best in mine of what I have tried through it, I haven't tried lighter. 180 gr has a lot of fliers for me.
Not sure why but my pencil profile 22" 1:12 mag fed lever Win 88 in .308 is not as picky. In fact after I get my new scope on it I would like to start walking the SMK 175 out 1000yards.
Someone recently told me it is the jump to the lands. In the same conversation someelse said it is the primers, they are too hot and and have to much pressure variance. In the lighter bullets he didn't think that the quick pressure pulse of hot primers deformed the bullet ass end nearly as much.
I actually think it mught be a combination, as the Win .308 was designed to run out of 1:12R twist barrels, I don't think the slightly slower Vepr Twist is the whole issue.
But every rifle or pistol will definately have a favorite diet.
If you hand load try loading down a little bit to get a more consistent slightly slower round and your groups should tighten up.