[Marek_Tucan]

Found some interesting info about post-wwII Czechoslovakian fortifications.
Pre-wwII forts were reactivated and rearmed, where deemed feasible (ie Western and Southern border, against Germany and Austria). Heavy fortifications got their 47mm AT guns replaced after some time by modified ZIS-S-53 85mm guns from T-34/85. Otherwise, the attempts to design mounts allowing either SG-43 HMG's or vz.52 LMG's were unsuccessfull due to perceived high costs. The forts remained till their deactivation in 1990s armed with pre-ww2 vz.26 LMG's and vz.37 HMG's, both in 7.62x57mm.
After war, manz projects were made but in the end, onlz two main fighting objects made it - KZh-1 which was generallz a basic prefabricated pillbox for LMG/MMG and KZh-2 which allowed limited use of recoilless weapons (T-21 RR and P-27 RPG). In limited (and uncertain) numbers, KZh-3 objects were built. These objects consisted of concrete underground base with a T-34/85 turret in a fully rotating mount.
Earlier experiments counted on Panzer IV's being buried in concrete, without engine etc. and with crew shelter, but experiments against a prototype revealed the construction to be too vulnerable to 85mm AT guns.