I have a Ruger M77 Tang Safety in 7 mag I picked up for a song. It's a decent shooter but truth is I have a .270 and a 6.5  x 55 AI, I don't really need another gun slinging 140-160 class bullets

I found an original .300 Win mag M-77 barrel for CHEEEEP, I'm considering a low buck switcheroo, which would give me something I need and don't have, a heavy hunting rifle.

My plan would be to true the action, set the barrel back a thread, and ream to headspace with something a little tighter than Ruger factory throat.

What landmines lay in my path?

I've barreled Remingtons and Mausers, and trued the actions, but never a Ruger. Anything I need to know?

Anyone got a reamer recommendation  for 200-210 grain bullets?