Can’t help you on African PG, but can speak to Deer/Elk in NA. A good 140gr .264 bullet will cleanly take them. .264 bullets have accounted for a number of deer & elk for new/recoil sensitive hunters in my camp. Most were mature cows, up to 600lbs ish. It’s an excellent choice when properly employed. We wait for close to perfect shot angles and keep ranges moderate. Mostly under 300, more due to inexperienced shooters than any concerns about the lethality of the weapon. The 260 Rem is the one we most commonly use. So if you were coming here to hunt elk, I’d say bring the 6.5x55 and we’ll hang meat on the pole, if the shooter does their job. Are there better choices, sure, but only if the shooter is comfortable with them. Will this one work well when properly employed, you bet.