IMPACT is available for both Fallout 3 and Fallout NV
This mod makes shooting bullets more realistic (and fun) by showing the impact effects and the associated damage to objects from bullet impact. For example, if you shoot at a building you will see the bullet hit the building, and there will then be a small hole where the bullet hit. This mod can noticeably affect game performance, so several versions with different performance impact are provided. It complements EVE which provides energy weapon effects, and not surprisingly was written by the author of EVE.