While it would be easy to assume dinos, especially theropods would taste like chicken, in reality they would have red meat similar to emus or cassowaries, because while to support the whole skeletal structure you'd need slow-twitch muscles that actively work 24/7, not just the legs for running.
More on that theory, dinos need to eat a whole lot. Like, a WHOLE lot to satiate their daily caloric intake needs. If their muscles are made from mainly quick-twitch muscles like chickens do, they'd starve to death if they failed on their hunt every-so-often: quick-twitch muscles are mainly anaerobic so you can't use them in quick successions, meaning if a dino fails on a hunt they'd need to rest and let the lactic acid dissipate before embarking into another try, or risk their performance be lowered, further impairing the success rate.
What's the minimum Caliber to take down 1-3 Tons Theropod? .500 Nitro? .600 Nitro?
I'd say the equivalent of .500 Nitro is already good enough if you aim for the trunk, their chest cavity would be mostly comprised of lung and heart anyway and if you manage to shoot them there they'll die eventually from internal bleeding. Trophy hunters, I'd image, would take only their heads and skin anyway so anything below the neck would've been ignored.
What's the minimum Caliber to take down 1-3 Tons Theropod? .500 Nitro? .600 Nitro?
.375 H&H is apparently the minimum legal caliber when it comes to hunting stuff like elephants or rhinos in parts of Africa, but apparently historical professional hunters preferred calibers like .404 Jeffery or .416 Rigby when it came to taking down big game like that. AKs are apparently a pretty popular choice when it comes to poaching rhinos and elephants in Africa, so 7.62×39mm or comparable should also probably do the trick, though it is probably safe to assume that the process would be significantly messier than it would be with proper big game ammo.
