I haven't checked lately, but Sierra was showing a max charge of 65 grains RL-22 with their 160 grain, 7mm Rem mag loads. I worked up to that in a couple of different rifles, with excellent accuracy results and easily surpassing 3,000 fps.
Guys experience is like mine.
It is a fact of life that you cannot baby a 7mm Rem Mag and get the vlocity from it that the cartridge is capable of delivering. This does not mean that you want to do anything foolish or dangerous...simply that the loads that are max will vary rifle to rifle due to a number of factors; and to get it to potential,you might need to tweak manual loads a bit, and velocity will not show until you get near top (but not dangerous)charges.The cartridge is not really unique in this regard....300 Win Mags are very much the same, and 264's are touchier than hell near max...
Frequently, magnum cartrdiges will not show their "stuff" until max loads are approached.....for that matter, neither will standard cartridges.
I watch the chronograph carefully when working up a 7RM load,and if I get to the point with a powder that is looking too over the top,but velocity is not yet "there", I switch powders, generally going slower which generally works.But going a bit quicker has worked, too.
For example, I had one 7RM on a M70 with Krieger 9 twist and a longish throat that gave 3080-3090 with the 160 NPT and BBC. It shot very well and was well behaved summer and winter with 70 gr H4831...cases had good life and accuracy excellent.
This load is close to max with the same bullet in the 7mm Weatherby magnum (see Nosler manual),yet was perfectly fine in
that 7 Rem Mag rifle and barrel,giving vels within 20 fps of what the Nosler manual states for the Weatherby...this and other rifles is the reason I say the 7mm Weatherby is nothing more than a free-bored 7 RM.
RL22 is a fine powder for the 7RM; but today with 160 gr bullets my first stop would be RL25,which has proven excellent.Next up assuming R25 did not work, would be H1000 or 7828.
. Just don't tell anyone 
. One thing I noticed (that I like) is that charges with RE25 fill the case better (more load density) say 95% as compared to RE22 which is running around 80%. I'm curious to see how the rifle will do with the new powder. Does anyone know how temp sensitive RE25 is? I wish I could take another day off of work to go and shoot/play 