I have the 300 rum and it is a very accurate round. The 7mm should be just as good. It would be best suited for heavy bullets of great construction because of high velocity. It will kill anything you need to kill... period! The recoil is strong but with practice you will find it manageable. Ammo is expensive but if you reload it is not such an issue.
As good as the core locks are, in the magnums I would go at least a 150gr bonded bullet. Your asking a lot for a 140gr bullet to stand up to that velocity at the closer ranges. Matter of fact, I'd look for a 160gr load if it were me.
The corelokt ultra should be fine as it's a premium bullet but i to would suggest the Nosler Partition. I use 160gr Noslers inmy 7 Mag for just about everything. The 150gr Scriocco is also a good bullet for long range shooting. I would try a couple of different loads & see which one shoots the best in your rifle.
I have a system I use in Whitetail hunting during the rut that seems to work for me. When I make a mock scrape in the area I wish to hunt I will place a couple of 35mm
film canisters (film removed of course) in the scrape after I have cleared out all leaves and other debris. The film canisters are filled with cotton balls and saturated with doe in heat urine. This keeps the urine from soaking in the ground and can be refreshed on each trip if needed. I will also use the tarsal gland of the buck...