The Desert Eagle operates with a rotating bolt and a gas powered recoil system. Timing in such a firearm is critical. Magnum Research does not recommend reloading. However, there are many successful reloaders of the .50 Action Express as there are of the more popular and plentiful .44 magnum and .357 magnum cartridges.
Here is a link to Magnum Research-recommended ammunition for all their Desert Eagles . . .
MRI Recommended Desert Eagle Ammunition