There are a few fairly fragile bullets currently on the market. These are bullets like the Nosler Ballistic Tip, Hornady's Vmax and SST, etc. These bullets open hard and fast, and work quite well in non-magnum calibers. I've used a 165 Nosler Ballistic Tip loaded in a .308 for years, and it works great without excessive meat loss. However, when these are pushed to magnum speeds, they become too explosive in my opinion. Meat loss becomes ugly...
There are two ways to ensure your 7mm RM doesn't shred meat all to heck and gone. One is to reduce velocity. This is fairly easy - select a 160 or 175 bullet instead of a 140. Some lighter bullet loads (like Hornady 139 Superformance SST) travel 3000-3200 fps. This is fast, and causes bullets to open dramatically and explosively. Heavier bullets travel a bit slower, and therefore don't open quite as fast. Some of the common 175 loads move at a rated 2800 fps. Bullets don't open quite as explosively, and this means a lot less meat loss.
The other option is to choose a somewhat harder, more controlled bullet. Something like a Nosler Partition.
A buddy uses his Rem 700 in 7 Rem Mag on everything. Moose, Caribou, deer. He uses one load: A handloaded 175 Nosler Partition. If works on everything, and isn't excessive in terms of shredded and mangle meat.
If you are worried about shredded and mangled meat, try a basic 175 grain load in the 7RM. It will act a whole lot like the old 180grain 30-06 load. It will penetrate and penetrate and penetrate somemore, but won't over expand, particularly is you use a somewhat controlled bullet.
Fro