Originally Posted by
GrumpyM4
And I would hold that the hole in effect turns into an expansion chamber and the expanding gas is then forced back into the original bore size causing turbulence flow that will still gas cut the steel on the trailing edge of the hole, especially since chrome has been removed. Friction, heat, thermal expansion, etc. will also factor into the speed of progression.
One simply has to observe the erosion on suppressor baffles to understand that even that far from the chamber, pressures and temperatures are still quite high enough to cause significant erosion over a relatively short amount of time and those items are not even in contact with the passing bullet. A quick study of blast baffles shows very visible erosion after only 500 to 1000 rounds.
Almost sounds like an interesting subject to do some testing on to get some empirical data.