If you look carefully, when a PU or a PSO-1 optical sight are installed, rifles that are compatible with these scopes still have the standard iron sights. These iron sights could be used if I'm forced to engage an enemy who is close by. Please add an option to use these iron sights, as this is possible on many Soviet weapons (SVD, SVU, Mosin, AKM, RPK-74M, PP-19-01, SOK-94, VSS, VSK-94, Vepr, SR-3M, As-Val and 9A-91). The zoom of PU and PSO-1 scopes is too high and, if installed on a weapon, they lose the capability of close quarter combat because you cannot install 2 scopes on these weapons. Adding what I suggest would fix this flaw.
Please take a look at how Red Orchestra 2 did this, a game that was released in 2011: https://streamable.com/0ba4i
Then, SpecterDR has also a feature for iron sights, so it should be possible to use this: https://i.imgur.com/mTyp5mG.png