My first import ever, however, I had some help from BraveDragonWolf.

I took the Assault Rifle model from Blaseth's Spartan models and imported it over the Super Scope.

It works fine in-game, but sadly I had a problem after removing one annoying polygon (the textures got insanely messed up).
This glitch is barely noticed, but there's no freezing.
This happens commonly when using Snake (wierd, but it happens).
Marth can also glitch this rifle (although I was using a Sephiroth model, so I'm not 100% sure).

If somebody wants to help with the texture issue, please send me a PM so we can deal with it.

The first pic shows Tails using the rifle in a battle with Master Chief (not seen there).
The second pic shows the Rifle as it should be.
The third one shows Shadow holding it (notice it isn't glitched).