I believe that much of your answer can be derived from the photo above with the line up of cartridges. All appear to have the same bullet so we can then see how deep into the case the bullet is seated to meet the desired length.
If my esimate is correct these are 7-08, ?, 7 SAUM, 284, 7 WSM, 280, 280AI, 7RM, 7STW. I observe the overall length available in the 7RM and presume this is due to the longer action and magazine box of the Rem 700 action. On both of my 7 Rem mags the 700 can be loaded to longer length, COAL, than my Mauser Mk X. My Rem 700 also outshoots my Mauser with the same load. I haven't tried to modify the load for the Mauser as this is really just a back up.
If my viewpoint is correct the 7 RM can be loaded more efficiently for a higher speed with a 180g bullet. There is also a later photo in this sequence of the short mag cases and the bullet I presume to be the 180.
Me, I hunt mostly with a 280, Rem 700, fixed 4x Burris Supreme that will put several different loads into about 1/2 inch.
