Hi Sid, I'm actually from Sydney Australia not Europe. The 280 Rem came out of the blue and a very recent acquisition. Brand new M70 Super Grade at a good price probably due of the unpopular calibre. I was surprised though when I could find 150gr Precision Hunter ammo in stock and at decent prices! Shoots it ok too. That sealed it - was never going to be an AI then plus the twist rate.
I haven't got any game in particular in mind. Always a fan of the M70 and after hunting Africa in 2019 with my M70 Kudu Custom 375H&H became an even greater fan! Ironic that the only animal on my list I missed out on was a Kudu. Kudu Services is what my gunsmith trades under.
Back to the 280Rem I'll leave it as is - it's a good calibre which becomes great if you hand load. If I need more speed I have a 7mm Rem. One pleasant discovery is the milder recoil compared to a 30-06. Not that the 30-06 is bad but you do feel the difference and it is just that "feel" so it's a personal opinion.
The 7x57 is great. Used my PH's rifle an M98 to take a Nyala and Warthog. So mild yet so deadly!
Hope you get to do your African trip. Well worth it.
Rifle imports are a challenge. It's good to hear your M70 in Portugal found a good home in Australia! Those M70 CRF rifles make really popular options for African Safaris. You have your share of tough critters in Australia too! I've known a few guys that took some tough game in the outback over there.
Unfortunately, I've had some setbacks on the Safari front. After a shoulder rebuild, a hard-hitting 470NE double isn't really viable anymore, nor any of my big boomer bolt actions. Add a job layoff and the trophy fees for the big animals, not to mention the big 5, are out of reach right now. My little 7 Mauser or the 6.5x55 (6.5 Swede) and some smaller plains game are still a post-COVID dream. Both of those calibers are drastically underestimated and often overlooked by people in the USA chasing the latest boutique cartridges (Noslers, Ruger Compact Magnums, ...) that are all the rage on forums and in the gun magazines selling print ads and copy space these days.