I agree with @mordecaiB in that it generally requires a skilled user, whether from military or hunting, to make use of iron or even ladder sights to achieve a solid hit at range, there are still viable weapons from the WW2 era that I’d be more than willing to use in the Ukraine.
In the existing thread on technicals, the argument is to what extend modern small arms are effective in taking out the vehicle. The empahsis being on something that doesn’t expose you to counter fire for length of time but disables the vehicle. And while high rate of fire weapons would be great, the efficacy of the common 5.56 would be an issue in terms of shorter term stopping power.
Here, something like an old fashioned BAR could make a welcome appearance, in that you have a WW2 era weapon (fully deployed after 1938), chambered in what would be considered full power battle rifle ammunition (30-06), with automatic fire fed from a removable magazine.
Again, it would not be ideal in many circumstances, but would have advantages over modern weapons in a few, although (and again true for most weapons considered in this thread) having enough of an ammo supply in Ukraine seems unlikely to make it effective for any length of time.
It does lead back to mordecaiB’s point though - we increasingly use small arms for suppressing fire and/or attacks on other dismounted troops - the killers are drones, artillery, guided munitions and the like. It’s a luxury of a rich, well equipped army, but one that, if the war continues, may not be fully applicable to that of the Ukraine if the political will to continue support wanes.