Originally Posted by
super_hunt54
Only about 20% more powder if you take the average .270 load of IMR 4350 at 53.5-55 grains which is about the average in the books.
News Flash for you there Jake, Nitrided barrels will last a bit longer but not THAT much as you seem to think. RR is dead on correct in his assessment of around 600-800 rounds with a normal CM barrel. You can MAYBE double that assessment to 1200-1600 round count with the Nitrided barrel but that round you are talking about will be inherently hard on the throat. Just the nature of the beast.
The calibers that ive seen that have a tendency to be hard on a throat are usually significantly over bored. Massive amounts of powder and a very tight burning cylinder. I think the 257-6.5-270stw-rum or even larger could fit this category. The 300 win mag capacity is quite efficient for 277 and 7mm bullets. The 7mm Jarret, an awesome round is a 300 win mag necked down to 7mm. According to several gunsmiths i have used, throat erosion is highly determined by the operating temperatures. Meaning long strings of successive shots do more damage than a few high powered shots.
Hey this isnt for everyone, i was replying to the op with real world experience on his question.