Barrel life is proportionate to the number of pounds of powder burnt at a given pressure and a given barrel diameters An example is a 222 Rem shooting 20.5 gr of powder at 50
000 barrel life is approx. 3,000 rounds Where with a Swift shooting 39 grs of powder at 3800 fps would have ½ the barrel life as the 222 plus an even shorter life due to the extra 5000 lbs of pressure 55,000 for a barrel life of under 1000 rounds. Take the 300 Win Mag ..shooting 80 grains of powder at 55,000 psi is about ¼ the life of the 222 plus a small bonus for the extra 5000 chamber pressure. This can be confused by the rate of fire as the faster the rate of fire the excelerated shortness of barrel life. Barrel life of a 223 firing one round per minute will be considerably longer than when fired from a AR15 in semi auto. I would always give a rifle barrel to win a match so I have never been concerned about barrel life. If it is a deep concern to you pull the pressure off till you start to see A loss of accuracy and never shoot it till it gets hot enough that you can't hold your hand on it. Or look at it as part of the cost of having a hot rifle like driving a hot sports car.