My416
Welcome to the Forum. I have hunted with Ruger No1's and think they are very fine rifles. I have not hunted dangerous game with one but would.
It is the man and how he handles the rifle that determines its suitability for dangerous game. A good man with a No1 can shoot just as fast and accurate as the average man with a bolt action. I always had extra shells in a buttstock carrier, and could shoot, load, and shoot almost as fast as a bolt rifle. Once the magazine of the bolt rifle runs out the single shot will prove faster for the next shots. Plus single shots never jam, nor dump ammo at your feet.
In a CLOSE charge the single and the bolt are both one shot, winner take all.
If YOU practice and can keep your cool the single shot will do for DG.
As to the 416 Rem Mag there have been some complaints of high pressure with factory ammo, just test you ammo or shoot reloads.
Plus it just seems you just "hold and squeeze" a little tighter when you are using a single shot.