There were several different barrel contours used with factory adjustable brakes in the mid 90s that I've had. The sporter barrels flared at the end up to the brake size. The medium heavy barrels Ive got were also straight fluted and tapered down to the same size as the adjustable brake. The magnum contours I've seen were a lttle heavier and longer but also tapered to the size of the adjustable brake.
With no pics I am gonna go out on a limb here and assume youre takling about the Savage adjustable brakes. The features of the rifles were designated by the letter codes after the model number and the code for the adjustable brakes were AK.
Does it have texture between the barrel where the brake starts and the vent holes?
If so it should twist to turn it off or on. They sometimes locked up if not properly cleaned and lubed. If you have an adjustable brake and it's frozen it can be freed up with penetrant and time and working it back and forth with a rag.. If its really frozen then afer penetrant and a couple of days wrap it with a leather belt as a cushion and grab it with a pair of pliers and rock it back and forth a little at a time till it frees up.
Hope some of this helps
BHJ