Download de "Unkn0wns CSGO Texture Installer" in http://unkn0wn3d.com/csgo-skin-installer/

Step by step:
1-Open the "Unkn0wns CSGO Texture Installer" and set your CS:GO directory if you need!
2-Click on "Select File" and choose your skin.
3-After this, under the "Replaces" you copy and paste this (For this skin): models/weapons/v_models/pist_glock18/pist_glock18.vtf
4-And click in "Install" 
5-After copy and paste this (It looks the same, but it is not): models/weapons/w_models/pist_glock18/pist_glock18.vtf
6-And click in "Install"
7-Okay, is done, now you can play with this skin!

Toturial by:BrunoMendes
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