Good luck on finding one of these. I looked for years trying to find one. I finally gave up and bought a 284 rifle. It is now a 338/284 and I really am impressed with how that round performs.
Do you have a Savage 99 284 action? The carrier assembly for the 284 is completely different from the regular Savage actions and would require a groove be cut in the receiver to retain the clip that holds it. The cartridge cut off is also unique.
If you want more information about this send me a PM and I will try to help. There is not much information available on the Savage 99.
