I did read about how the 1950’s BTR-152K, the enclosed version, had an NBC protection system. How well did it actually work?
It wouldn’t take much to be affective. Even a slight differential in pressure keeps fallout from entering the vehicle. It doesn’t even have to be airtight as long as there’s positive pressure within the vehicle.
that doesn’t do much for gamma wave radiation tbough
Overpressure systems are not designed for that. Gamma radiation is the most penetrating of all. It takes quite a bit of lead to stop it. Even Russian vehicles with anti Neutron cladding generally limit it to turrets or hatches.
I did not find confirmation in Russian.
For the effective operation of anti-radiation and anti-chemical support, it is necessary to ensure the tightness of the hull and create excess pressure inside, as is done for the T-55 tanks. For the BTR-152, this is simply impossible to do. In the BTR-152K, they simply installed an exhaust fan. And the version with a roof can certainly be considered more protected from radiation than the version without a roof.