The AMT Automag V, in .50 Action Express.
This is a monster of a pistol, the Desert Eagle chambered for .50AE can at best be described as harsh in recoil, being a very heavy and gas operated locked breech gun. This is all short-recoil, and with a narrower grip, you WILL feel this against your palm.
To my knowledge, all Automag Vs have ported slides and muzzles, to help counteract the no doubt stern muzzle flip.
These are some good pictures of the pistol in general, and shows what the AMT Automags have in common with the classic 1911 (such as the slidestop and barrel bushing), and where it differs, like the slide mounted safety, but also the absence of a grip safety. The bore on this pistol looks very crisp, likely this has been fired little, if at all.