Gunfighter34ID

Been using Vilas' M14 and M21 in user-made missions. They used to work fine but lately I'm getting a "permanent muzzle flash" when I use the mods. I've got the guerilla and Vietnam packs installed and a few others, and like I said, no prior problems. Now when I load the game and select any of Vilas' weapons I've got a muzzle flash at startup and it never goes away. Is this a known issue and is there a fix for it? Sorry if this is a n00b question but I like using these weapons and I want a fix.