22-250 913gr/sq in 36gr 243 948gr/sq in 44gr 25-06 1059gr/sq in 55gr 6.5x55 840gr/sq in 46gr 6.5-284 950gr/sq in 52gr 264 win mag 1042gr/sq in 57gr 270 win 912gr/sq in 55gr 270WSM 1077gr/sq in 65gr 280AI 900gr/sq in 57gr 7mm Rem Mag 1011 gr/sq in 64gr 308 win 605 gr/sq in 46gr 300 win mag 881gr/sq in 67gr 300WSM 855gr/sq in 65gr 300 Ultra mag 1184gr/sq in 90gr So here is the breakdown 600-700 Don't worry your grandchildren will likely be shooting from that barrel. 700-800 Still pretty mild by any standard. 800-900 Always let your barrel cool between strings if you want many years of service, getting hot. 900-1000 Hard on barrels regardless of cooling, but acceptable barrel life can still be had. 1000-1100 Barrel burner alert, with these expect to start loosing some accuracy quickly, often before you hit 1,000 rds 1100+ Buy stock in Shilen because all of your money is going to them if you shoot alot. There are other factors involved too like barrel heat, brass design, and peak pressure but they are minor compared to the volume of burning abrasive being forced down your barrel at supersonic speeds. If anyone else would like me to run the numbers of their pet cartrage/load just let me know. I hope this clears things up for us a bit.