What bullet weight for the 7mm Mag?

You can sort of look at the 7mms you have as "skinny" 30-06 loads,they will like 160s, and the Weatherby might do better with 175s because they "tend" to have longer freebore (would have to gauge at some point). Like a 30-06 with 165 and 180 grain bullets, those tend to be in the "sweet spot". Does that guarantee great accuracy,no,but with the common barrel twist and weights they should be best. Even with 150s you will get good Sectional density and BC numbers,but like in a 30-06 some don't do as well with 150s.

Almost anything 243 and up will take deer, I'd go heavier for bear and the 7mm RM and 30-06 is what I see most in the field deer/elk hunting. You do have more bullet choices now too, I use controlled expansion and bonded core bullets in my rifles because I handload and can load them cost effectively. For deer you don't need "premium" stuff, barely do on bear in most loadings,but with 7mm Mags you can really tax a bullet's terminal performance and get jacket/core separation especially on close in shots.

Just putting that caveat in, I've never had problems using what I do, and the factory Rem Core-Lokt I use to shoot did fine most times too. There are loads like the Federal Fusion,Hornady Inter-Bond,Winchester/Combined Technology stuff with Accu-Bonds (not Ballistic Tip,too frangible for my taste) and other stuff out there.

You might have to explore a couple loadings and your accuracy needs might not be same as mine,but getting near 1.5 MOA should be fine.

Accuracy will depend on your individual rifles' barrels. The entire load, not just the bullet, will be individual to each.

175 grainers are going to have a strong tendency to punch through a deer before they set up. Even 160's are likely to do so. On the other hand, 139/140's may not stand up to very high striking velocities if they hit something like shoulder bone at close range. I'd look at the 150/154's as a reasonable compromise.

What does the store carry the most of.? that is probably the most common and what people think shoots best. And like said above it depends on the riffle.

You are not going to know what bullet they like until you try some and see eh?

Mine likes Rem cor-lokt 150's. Yours may not.

Mine shoot 145 grain Speer Spitzer OK . They have never failed to exit a deer .