I noticed an interesting little tidbit while watching Forgotten Weapons- the PTRD is meant to be recoil-operated, in a sense that firing will open the bolt and eject the shell for you.
Currently what we see now is that you need to manually open the bolt before loading the next cartridge.
What that means is that due to the manual opening of the bolt, the PTRD in game has a slower reload rate than it should.
Not the end of the world but something to look at fixing.