The aforementioned Ruger M77 tang safety with lengthened mag box is currently shooting the 168 VLD @ 2835 fps with 53 gr of RL-17. OAL is 3.050"
If I were to go with a long action for the 284 it would be long throated and twisted fast enough to shoot the 180s. Otherwise a short action would work fine.
Heck when I had to deal with the original 2.9" Ruger mag box I was able to shoot 140 and 160 partitions with a 2.850" OAL. Still got 2950 fps with 140s and 2800 fps with the 160. It was my only rifle and it worked fine for coues wt, elk, javelina, coyotes and jackrabbits till I acquired other rifles. It is still one of my favorite rifles