The gp37_gl_mod.zip file you have requested: Shadow of Chernobyl / Mods / Weapons / GP 37 Grenade Launcher Mod - 4.04kb 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:
"Makes everyone's favorite AR just a little better by enabling an attachable grenade launcher and silencer."