The avt40 is a very good weapon.
Basically you get an SVT40, no problem with that, accurate rifle. In addition, you can now shoot through most walls, making it plain deadly.
Been called a wallhacker at least once every two maps since i'm using this baby.
And the full auto is not to be underestimated. Any indoor setup with walls will pretty much be your playfield if you now what to do.
Station is a good exemple, in the frontline building you can go on a rampage as germans are pushing, pre shooting walls like crazy.
Just switch to full auto & shoot bursts of 3 bullets through walls, next to doors, wherever something "sticks out", wherever german chatter comes from.
Same goes for grain elevator. Just aim a bit lower than usual (belly) & get ready to counter the kick as soon as you fire.
A 3bullet burst through a wall is generally a kill, i gotta say after leveling that kar98k to 50 that this is my favorite weapon.
Hell you could divide the clip size by two & remove the full auto ability it would still be my favorite just because of the penetration power & the "zomg died through a wall gotta be a cheat" factor.