mike H wrote:..Is there any solid documentation to support the belief that twenty shot strings are measurably more damaging than fifteen shot strings,thinking that very few F Open shooters would have ever shot a twenty shot string in Australia?
Even the old timers from the 303 days refer to 20 shot shoots as "barrel burners". I can only go from the experience of feeling the barrel but I'm sure a scientifically sound study would show the same thing as far as temperature goes. The barrel surface is much hotter after 15 shots than 10, and hotter again after 20. And shooting faster definitely heats up the barrel much more. So a 20 shot string shoot would be the extreme case. As far as the relationship between throat erosion and barrel temperature, it stands to reason that a hotter barrel will accelerate the erosion process, which is said to be caused by a combination of heat and pressure.
Here's some links which may be worth a look :