Magnum Parts are an item in Resident Evil 2.
"They look like parts for a magnum."
Located in the Weapons Locker of Birkin's laboratory, these parts consist of a reinforced slide and custom ten-inch barrel for the Desert Eagle Magnum. They greatly increase the power as well as the recoil of the gun.
The Weapon Box Key is needed to unlock the Locker.
An infamous typo exists in the American release of the game, where the Magnum parts are actually called "Mugnum Parts". This typo is consistent with re-releases of RE2, even on the Gamecube. But it was fixed in the DualShock version.