The Hodgdon load data on their website shows the .338-06 producing higher velocity than the .35 whelen with the same weight bullets. According to Hodgdon, w760 will produce 2,675 fps with a 225 grain bullet in the .338-06 while 8208xbr will produce 2,618 with a 225 grain bullet in the .35 whelen (these are the highest velocities listed for each). Using the same powder, imr 4895, produces 2,594 fps in .338-06 but only 2,553 in .35 whelen.
This seems counter-intuitive to me. Both have the same case capacity and the .35 has a larger area for the gas to push against which should produce higher velocity.
The culprit appears to be that the maximum allowable pressure for .35 whelen is 50,000 cup while the max pressure for the .338-06 is 63,000 psi (according to the Hodgdon load data). According to the following source, 50,000 cup is equal to about 58,000 psi.
https://www.shootingsoftware.com/ftp/psicuparticle2.pdf
So why would .338-06 have a higher allowable pressure than the .35 whelen? Both started as wildcats off the .30-06 case, so they will be chambered in the same rifles.
This seems counter-intuitive to me. Both have the same case capacity and the .35 has a larger area for the gas to push against which should produce higher velocity.
The culprit appears to be that the maximum allowable pressure for .35 whelen is 50,000 cup while the max pressure for the .338-06 is 63,000 psi (according to the Hodgdon load data). According to the following source, 50,000 cup is equal to about 58,000 psi.
https://www.shootingsoftware.com/ftp/psicuparticle2.pdf
So why would .338-06 have a higher allowable pressure than the .35 whelen? Both started as wildcats off the .30-06 case, so they will be chambered in the same rifles.