This is a high detail but low poly custom variant MK18 Semi-Auto assault rifle.
The gun is perfect for FPS games, or 3rd person shooters or even top down shooters. His model is free to use in your game/animations and I hope you find it useful.
Any issues/questions or requests for this gun including changes to the barrel, stock or making any other sights just leave a comment and Ill happily see what I can do. Thanks!
It has 3 main textures that are in the pictures located above, make sure you you right click them and save image as... and when you open the 3DS Max file it will ask you for them and you can provide the location.