Here's the follow up question. Does the shorter and fatter case that holds a given amount
of water slow barrel wear more than a taller slimmer case of the same capacity? I've heard
time and again the short fat case is more efficient compared to the tall slim case. But is there
a difference in damage caused to barrels?


The REM 300 SAUM and the 375 RUM both do very well with the math formula provided by a
poster in the earlier thread that I started on the OVERBORE topic. In other words they come
very close to maxing out on case capacity compared to barrel life.

Link to earlier thread: http://forums.accuratereloadin...4711043/m/8841070531

From 10th post of above thread: Case capacity in grains of water divided by the area (in
square inches) of the bore cross-section. This gives an index number, anything over 1000
is Overbore and will tend to be hard on barrels.

Comes down to velocity and heat of the gases in the bore. Shorter/fatter tends to heat up more than longer. Also, necking down heats up the gas and increases velocity.