many are taken here with that combo and pretty sure close to where the world record was taken with .303
The 303 Brit is a great cartridge and when the rifles it's chambered in are well maintained and accurate, will handle anything that's legal to hunt in Canada.
It still has a huge following and either meets expectations or gets dissed by snobs on both sides of the argument.
The people who developed the cartridges of that era had their stuff together for the most part and did a lot of extensive testing/development to wring the best out of those cartridges, with the components available to them at the time.
Today, there are far better components, such as powder/primers and bullets available, which makes caring for those old firearms much easier and in some cases more accurate.
Because the bore diameters of those old rifles are not very consistent from one rifle to the next, some just don't shoot well.
CIL, right up to the early seventies used to offer 30 caliber bullet diameters from .307 to .318 in .001 increments. They had standard diameters such as 308/312/318 readily available, but would make up 1000 count lots of any of the other diameters if you placed an order with the company. Took about three months to get the bullets by Greyhound Express.
The original bullet designs back in the day, had "exposed lead" bases and this took up most of the variations in bore diameters, as the pressure against the lead caused it to push forward and force the jackets to obturate into the rifling, for acceptable hunting accuracy.
Those bullets are no long made, by anyone, to my knowledge.