Well, ye. It's gone. I think its due to this Better Smoke and Embers by Toasty Fresh or due to EVE by weijiesen. As I dont have any other mod installed that could've changed the muzzle flash. So my question is ? Could some one send me the files of the original muzzleflash/link me to a mod that'll have a working muzzle flash ? It's kinda annoying not to have one in-game and it takes away from the immersion/realism.

(Cant post direct links to the mods yet.)

That's a strange one, any chance of a screen shot so i can take a look at problem?

EVE doesn't touch ballistic effects.

Better Smoke and Ballistics includes some optional versions, is it possible you installed the realistic version? because that pretty much removes muzzle flashes completely.

Check in your data folder and see if there's any files under Meshes\Effects\MuzzleFlashes\
if there is, try to find out what mod they came from. if you can't find out just delete them and the game will load the original files from the BSA.

I hope this helps.   

I removed every map named "Muzzleflash". After this it worked fine. It seems like EVE and FOOK and Better Smoke and Embers added/changed muzzleflashes. Thanks for the help

Oh I'm glad you got it sorted.

I don't know much about FOOK and whats included but i can say that it wasn't EVEs doing.

Have fun!   

Yeah, if in doubt, removing stuff you don't want _usually_ returns the vanilla items as they're in the bsa's that come with the game. You shouldn't need loose files to make vanilla stuff work.

Now some muzzleflashes are "missing textures" box. Mostly on modded guns. Vanilla guns and some modded ones are fine. Also, it was a texture from the Better Smokes and Embers that made all the flashes invisible.

The exclamation mark box indicates a missing mesh.

I guessing that when you deleted everything with muzzleflash in it you also removed modded weapons custom muzzleflash effects.

Simply find the mod that adds the weapon and reinstall it, that should fix it.