Gmod gun shell errors

I have been playing some online games in gmod and have noticed that many of the guns shoot errors. A lot of cs:s guns shoot errors but its not just them. It there a way that I can look at the guns lua file and see what model I am missing so that I can get it?

Thanks

Do you actually own Counter-Strike: Source itself or have you downloaded the models?

I have downloaded the models, but its not just cs

Not the models, do you own CS:S?
And have you downloaded it fully?

i do not own cs, but some of the guns arent cs

I actually get the same types of problems for muzzle flashes and I own CS:S

hopefully someone can help us