2020, still no fix

SWEP.CSMuzzleFlashes = true
Add that to any of the weapon files you are editing. To make the change for all of them find the folder bobs_gun_base and edit the shared.lua file and add the line. This will make all the muzzle flashes for the guns to use the Counter Strike: Source muzzle flash instead.

What I did was put the m9k folder into my servers addon folder, then did the above to the bobs_gun_base, saved it and got into my server and the muzzle flash was fixed

As long as the server host has done the same, there isn't much you can do if they haven't done it.

Muzzle flash problem is still current.

download the yee berrata's, it removes the muzzle flash effect

引用自 FatPigeon( ͡° ͜ʖ ͡°)：

SWEP.CSMuzzleFlashes = true
Add that to any of the weapon files you are editing. To make the change for all of them find the folder bobs_gun_base and edit the shared.lua file and add the line. This will make all the muzzle flashes for the guns to use the Counter Strike: Source muzzle flash instead.

I know this comment was made four years ago, but there doesn't seem to be a file like that related to the addon, at least not maybe anymore

引用自 ReddSnake：

引用自 FatPigeon( ͡° ͜ʖ ͡°)：

SWEP.CSMuzzleFlashes = true
Add that to any of the weapon files you are editing. To make the change for all of them find the folder bobs_gun_base and edit the shared.lua file and add the line. This will make all the muzzle flashes for the guns to use the Counter Strike: Source muzzle flash instead.

I know this comment was made four years ago, but there doesn't seem to be a file like that related to the addon, at least not maybe anymore

When you unpack the addon, inside of it you go lua > weapons > bobs_gun_base. In bobs_gun_base is the shared.lua file and then you add:
SWEP.CSMuzzleFlashes = true
This variable itself probably doesn't exist in the file so just copy and paste it into there and it should work.