It's a function of available real estate at that point. If an aftermarket barrel is fitted and the person doing it elects to run the breech ring down to minuscule amounts, then your likely to have an issue if you run any M16 extractor. That is something outside of my control. Keep it within dimensions known to work and its smooth sailing. The magnum and "boomer magnum", .545/.590 bolt face cartridges seem to be the ones most susceptible to this. .390, .450, and.480 runs well below the bolt circle periphery.
Super snug breech rings do nothing. The gun doesn't shoot better, it doesn't function better, it does nothing. -other than complicate things on a number of levels. Dirt, additional items later, etc... If it did, I would expect to see actions using it routinely outrunning those that don't. (Rem vs Tikka, etc...)
C.