The gp_37_addon_fix_non_degradable.zip file you have requested: Shadow of Chernobyl / Mods / Weapons / GP 37 addon fix + non degradable - 4.64kb is not available. Perhaps try browsing all files for the game S.T.A.L.K.E.R. Shadow of Chernobyl and upload any files you want to share or are missing. This is the only information we could locate:
This mod fixes the GP 37 to allow the M203 Grenade Launcher and silencer to be attached. It also makes the gun non degradable. See readme file for full description.