In this post I am touching on several BIG topics, but I'll try to sum them up with one question. 22" barrel length is common to many 30-06 rifles. Since a 30-378 Wby has very close to twice the powder capacity, why doesn't a 30-378 rifle have a 44" barrel ?? This would give each rifle the same expansion ratio. ??? On a side note, this should also give the 30-378 bullet about 1.414 times the muzzle velocity of the 30-06 (same bullet weight). I.E., 3800 fps vs. 2700 fps. I have done a lot searching to find graphs of the internal pressure traces of large capacity cartridges, to compare with a typical 30-06 pressure trace, and have not found good comparative results. I have done this with gasoline engines and compression ratio, which is a VERY similar situation. Aside from the inconvenience of carrying around a very long barrel, I see this as a simple engineering exercise in scaling.