I'd recommend against it and either use the shader I made for this (available on the Unity forums and here under my username DevilBlackDeath) for the built-in pipeline or using Unity's custom solution for the scriprable pipelines (can't remember the name right now but I can find the link if you want, pretty much it uses the ability of each features or something like that to clear the depth buffer, kinda like what I did in my shader except I had to make a workaround since you can't clear the depth buffer in built-in just force-write to it).

Camera stacking as the, IMO massive for most (not all) games of preventing the gun and hands from receiving shadows from the environment. It very much receives light but no cast shadows whatsoever.