There are some bulletins which mention like "Conscripts' and Grenadier's '
rifles' have 3% increased accuracy"
and there are other ones which just generally mention like "Conscripts and Grenadiers 2% reduced cooldown"
A random guy said that the upper one only applies to Mosin-Nagant and Kar98k because it mentioned rifles only. Not PPSh-41 and MG42. The lower one should apply to all weapons the squads hold.
However, according to what I've found from raw datas from
https://coh2db.com/bulletins/index
both bulletins seem to apply to MG42, but not PPSh-41.
It might be kinda unfair, I think.