I find this thread very interesting as i have a model 7mm SAUM on hold at the local gun store. John Haviland wrote an article for Handloader April 2005 no.234 where he tests the same rifle with the 22" tube, here are his results with the factory loads:
140gr Rem psp core-lokt ultra- 3,090fps .77" *average of three, three shot groups
150gr Rem core-lokt- 3,090fps .90" *group average
160gr Rem core-lokt ultra- 2,893fps *1.82" group average
The 22" tube didnt lose as much velocity as i would have thought
