If I lightly push the disconnector, or hold the pistol muzzle-up or upside-down to the rear it engages the hammer and operates fine. If I assemble it and try to operate it upside-down the disconnector gets stuck under the right "pin" of the sear. When fully assembled the DA works partially some of the time. It seems that the hammer will slip off the sear early some of the time, not even cock some of the time, and work normally some of the time. It also seems that the hammer doesn't fall past its uncocked resting position when dry-fired. With the pistol assembled if I dry fire it and try to push the hammer forward with the trigger still pulled the hammer will not move past the safety notch on the sear, making me think that the hammer wasn't fully cocked anyway (since the sear is still "down"). Also, the finger on the spring that powers the hammer sits to the left-of-center in the pocket in the hammer. The odd thing about all of this is that the gun seemed to work fine when it was packed with grease (albeit sluggishly of course).