ORIGINAL: stubblejumper
Throat erosion is caused by a combination of heat and pressure.Large capacity overborecases that burn more powder will erode throats at a faster rate than small capacity cases with the same bore size.As well rapid fire that causes the barrel to heat up excessivelywill accelerate throat erosion significantly.Letting the barrel cool between groupswill extend barrel life.If your accuracy begins to deteriorate it may be due to throat erosion but it may also be to copper deposits in the barrel.
this is exactly what I have always been told. I would first use a good copper remover (benchrest, schwedes (sp?) ) to try to get your barrel back to original condition, if accuracy is still bad, then take to a good smith and let him check the rifling/throat with a scope. It can be difficult for a person who doesnt know what they are looking for to use a scope properly. Do you reload? if so you can monitor throat errosion by using the stoney point oal guage and constantly check your seating depths. If you notice you are seating your bullets further out to retain the same distance from the rifling you have throat errosion.