Reading various links about the high pressure, fast, short & fat cartridges: I read one that said you can get to the point where the pressure is so hot, it starts to melt barrel. (Thus shortening barrel life & causing erosion.) So, if this is right... what kind of pressures start to take us into the barrel-eating category?

Back in the 220 Swift days, barrels had shorter lives but that was due to velocity, I understand. (Never owned one, tho)