Wouldn't I have been unable to play Fallout 3 in the first place if Windows User Account Control was preventing changes from being made? Also, if it is indeed preventing changes from being made, is that what's preventing me from changing the model and texture of the weapon I created? Sorry if this sounds really obvious, I'm an absolute beginner when it comes to stuff like this, and frankly I'm still very confused. And another thing, you mentioned this in your first response to my post: When I saved the weapon, it saved as an .esp. I'm not really sure how I can make this weapon without making an .esp file. In case I wasn't clear, I'm not trying to replace the Xuanlong rifle with the rifle I created- I just used the Xuanlong's model as a placeholder, I still want the Xuanlong to be in the game, just as a separate entity from the gun I created.