If you understand the purpose of "pillars" you will understand that exotic/expensive pillars are not required (but Convenient), especially on a hunting rifle. What is required are socket-head action screws & an accurate torque wrench to adjust them the same every time.
I've never done a Rem 783 but I've done a number of Rem 700's & Win 70's. I have a small hobby lathe & I turn my pillars out of aluminum rod that came off a lawn chair. But before that, I used threaded lamp rods. These come in various lengths, threaded on the outside in either brass, steel or some sort of pot metal. The pot metal seem to be the best - plenty strong & easy to work. You can modify these very easily with a dremel or hand tools. If the receiver is round you can even match the curve with files but I think that is unnecessary. Better craftsman than me can install pillars & glass bed all at one time. I do pillars first then the full action. I also lightly bed the trigger guard/floorplate where the pillars meet. The idea is to use the pillars to attach the action/barrel to the stock as stress free as possible.
FWIW...
..bug