What makes a bolt gun Tactical?
I have two .308 bolt guns. One is...call it tacticool, since I don't know what tactical means in this context, while the other is a classic wood sporting Rifle. Both have detachable magazines.
Why? I think it is to make it easier to switch between loaded and unloaded, or vice versa. In many places it is illegal to drive in a car with a loaded rifle, so you take the magazine out and clear the chamber. Of course you can load and unload a fixed magazine too, but at some point you are managing loose cartridges.
I have heard that hunters often favor fixed magazines for hunting weapons because the magazine cannot come out or have the floor plate pop open spilling your cartridges on the ground. At the same time I have heard that laws or accepted practices in some areas require hunters to unload and reload several times each hunting day, which I imagine is why hunting rifles are available in both configurations, even from the same manufacturer.
In my case my tacticool rifle takes cheap 20rd magazines that are at least as convenient as plastic/cardboard ammo boxes. When I load (or buy) ammo I load it straight into 20rd mags, and when I go shooting I toss some mags in my bag and go. It makes storage, transportation, and everything else pretty simple.