Isn't PTRS rifle working a bit like a sniper rifle one shooting models with each shot? I know Guards was doing this on regular basis.
That's just an observation, I might be wrong here, hence the question.
PTRS rifles never killed models in 1 shot, as they only do 40 damage.
PTRS rifles have extremely low accuracy (0.05 near, 0.025 at max) because normally they hit vehicles with big target sizes. Against infantry, with the target size of 1 and accuracy lowering mechanisms such as cover or received accuracy modifiers, the PTRS will not really do anything at all except for the rare lucky hit.
Upgrading your conscripts with PTRS rifles is, in my opinion, a waste of munitions and manpower. You lose effectively ~30-33% of your anti-infantry DPS for what? The ability to be a threat to scout cars? Big deal. It's good in theory against OKW and their light vehicles, but the doctrine lacks any form of AI units or call in tanks so they can just make some Obersoldaten, Panzerfussiliers or JLI and you will have nothing to stop them.