Chris, You may have a problem. *Learning opportunity.
The 284 rotor retention is a *c clip* affair that fits in a machined slot on the inside of the reciever. It has no cross screw sitting in grooves like the regular rotor. That's the bad news. I just watched a beat up 284 sell for around a grand on GB, because I had the same thoughts, to build a DL in 450 Bushmaster. You really want to start with a 99C and a 284 magazine or a 284 with the rotory magazine.
The good news is I have a 284 that has both the machined groove inside the receiver with the c clip
and the rotor retaining cross screw, so at least dimensionally the 284 rotor could line up right to be held with the cross screw found on all other Savage receivers. Whether the cross screw alone would suffice is why you're the professional and the rest of us are not.
It is possible you may be able to use a 284 rotor in a standard receiver and cut some grooves in it for the cross screw to slide into, but I've not done it so couldn't say for sure.
If you would like me to disassemble the 99F 284 I'm talking about it will have to wait a while, we are moving beginning today, while working full time, so a slow process. I believe I have one of the c clips as well, and I can check to see if I ended up with a 284 rotor.
