Is it velocity or chamber pressure? I'm sure it's both, but which one has the bigger effect.
Hummer said:Somebody mentioned borescope and they are mighty handy but there is another tool that comes in quite handy. Erosion gage. If done right and good records are maintained you can track throat erosion and know where you are and determine what loads tend to allow the gage to move faster down bore.
http://www.geocities.com/binarybytes/308erosion.JPG [/quot
you don't need the guage, simply take seating depth measurements occasionally to track the throat. It's a good thing more people don't have borescopes. What it looks like and how it shoots are two different things. Shooting one powder/bullet combo over another in a 308 to gain more barrel life is just silly!