300 Ultra Mag... magazine parts problem

Can anyone help me out with this?? A friend of mine has a 300 Ultra Mag that was converted from a 300 Win Mag. The box magazine is too short for the factory loads. Is there specific parts that have an elongated magazine and follower specifically for this rifle?? I have been trying to locate some parts, but everything keeps turning up the Win Mag stuff.

Any help would be greatly appreciated!!

DK

The ultra mags used a magazine that was .220" longer than a standard long magazine. They accomplished this by splitting and welding 2 magazines together. They also used a longer follower. Sadly enough, these parts were discontinued in 2008.

Sharpshooter,
Not 100% sure but wasn't the cutout in the bottom of the action longer as well?