Topshot: What is your cartridge overall length? I ran a Quickload simulation on the Edge case (it assumes 113 grains case capacity) with the powder weight and bullet you stated and it show serious overpressure. But I suspect you have the bullet seated well out from the 3.6" COAL that Quickload has in it's database.
Could you give more details on your load?
Specificially the case capacity of your brass (grains H20 to fill level with the mouth)
and your cartridge overall length. Running overpressure loads will seriously shorten barrel life of most barrels using high performance cartridges.
Throat erosion is very non-linear. Throat erosion is the result of the hot propellant gas raising the temperature of the surface of the throat momentarily (for about two milliseconds up to the point where the steel softens. The propellant gas is not only very hot but also very dense and can push molecules off the surface of throat (which is exposed longer than the rest of the barrel) Barrel life drops rapidly once the steel peaks at a critical temperature. Thermal conductivity of steel is poor, so it's only a very thin layer which is lost with each shot near the onset temperature. Raise the temperature, pressure, or duration a few percent and a barrel can be blown out in a few shots. High performance cartridges push that limit. Those which exceed aren't popular.
The temperature rise for each shot is relative to the barrel temperature at the time of firing, Rapid fire or a high ambient temperature can have a significant effect.
Inspect the throat with a bore scope. Erosion is easy to see and identify.
