Thread: Is it Pressure or Powder Capacity?

Its generally powder volume vs bore diameter. The more powder for a given bore dia, the more barrel wear.
eg 243, 7mm-08, 308. All basically the same case / capacity. The 243 will have the shortest barrel life, followed by 7mm, followed by 308 with the longest.

Originally Posted by ChrisW

Its generally powder volume vs bore diameter. The more powder for a given bore dia, the more barrel wear.
eg 243, 7mm-08, 308. All basically the same case / capacity. The 243 will have the shortest barrel life, followed by 7mm, followed by 308 with the longest.

Yes if all cases are loaded to equal pressure.
However, I still suggest that if the .243 is loaded to low pressure ie 52,000 PSI and the .308 to 66,000 PSI the .308 barrel will have the shortest barrel life.
I take this idea off my theory that barrel erosion is based on heat (which is increased by pressure) versus time (more case capacity = more burning time) versus pressure build-up. Although yes I could be wrong

Originally Posted by Hermitage

Yes if all cases are loaded to equal pressure.
However, I still suggest that if the .243 is loaded to low pressure ie 52,000 PSI and the .308 to 66,000 PSI the .308 barrel will have the shortest barrel life.
I take this idea off my theory that barrel erosion is based on heat (which is increased by pressure) versus time (more case capacity = more burning time) versus pressure build-up. Although yes I could be wrong

Greetings Hermitage,
There is no doubt that reduced pressure will reduce throat erosion but the variable you have missed is projectile diameter. The .308 has 60% more throat area than the .243 ( circumference proportional to the square of diameter) so this may turn the tables on erosion. I suggest you do some comparisons using the barrel life calculator to get a better understanding of the effect of the four main variables. The calculator, while imperfect, is based on science rather than guess work.
Regards Grandpamac.