BB, I believe the Rem. Mod 11 did the same thing.

Long recoil operation
Long recoil operations are found primariy in shotguns, particularly ones based on John M. Browning's Auto-5 action. In a long recoil action, the barrel and bolt recoil all the way back as a unit. Once its rearward movement is absorbed by its recoil spring, the barrel is forced forward by the spring, where it unlocks from the bolt and returns to battery. The bolt, after compressing its own recoil spring, is held in the rearmost position until the barrel returns to battery. At this point, the fired shell has been extracted and ejected, and a new shell has been lifted from the magazine. The bolt is released by the return of the barrel, and is forced closed by its recoil spring. Long recoil operated firearms have a distinct "double recoil" feel to them, the "first recoil" being the halting of the rearward motion of the bolt and barrel, and the "second recoil" being the heavy barrel returning to battery.
Developed in 1900, the long recoil action is over a century old, and dominated the automatic shotgun market for more than half that century, before it was supplanted by new gas operated designs. While Browning halted production of the Auto-5 design in 1999, Frastill makes a long recoil operated shotgunnchi line, the AL-48, which shares both the original Browning action design, and the "humpbacked" appearance of the original Auto-5.