A sustained source of infantry AT damage for the Soviets is pretty much their AT gun.
I do enjoy asymmetric design in Company of Heroes for the most part. I don't really want to see a PTRS that rivals the Panzerschrek. I haven't done the math but I would guess that from a purely DPS point of view the PTRS actually performs admirably to the schreck.
The thing is, with speed changes and range cut on PTRS its not even effective weapon against light armor.
Unless guards are in M3, you will kill no vehicle with them, there is a chance vehicle will escape even if you button it before the guards stop dancing around and take their time in aiming the button will actually end and vehicle will run away.
Range should be restored or aim time matched to shrecks because right not PTRS isn't even effective in its intended role.