Unfortunately, there is no way to (easily) port new animations into Fallout 3 for weapon reloads. Fallout 3 has a set number of weapon reloads (A,B,C,D, ect.) hard coded into the game. To even add a new vegas animation would require some knowledge of coding and even if you could figure that out, you would completely replace one of the existing animations in the game. I have heard of sneaky ways of doing animations for weapons using idle animations, but I dont know how that would be done. When I replicated the Ranger Sequoia into Fallout 3 for my own personal use, to get the cylinder to work as it should, I used nifskope. I chopped out a 44. magnum reload cylinder with all the animations still attached and pasted it in place of the original ranger sequoia cylinder. The same can be done with FO3 weapons such as rifles or pistols.