Ransom,
You either have a burr or trash in the mortice the Carrier Block rides in, or, the side spring that powers the carrier block is not correctly installed/fitted or is lose. The carrier block should not start back down until the lever is about half closed on a stock rifle. The side spring should drop into the notch on the top of the arm that drives the carrier block. In this position, it holds the carrier block UP for the breach block to strip the round into the chamber, the lever will continue back and engage the top of the arm and start it back down. The spring powers the arm/carrier the rest of the way down in the mortice until it aligns with the magazine. Trash in the mortice or a lose side spring will allow the carrier block to stop and interfere with the breach block.
If there is trash (blow-by) or a burr in the mortice, it will stop the carrier block about where you describe. Also, inside the receiver there is a "slot" between the mortice and the area for the toggle links. A burr on/in this slot may also bind the arm.
If the spring is not fit to the frame, and is not tight, it will not exert enough pressure on the arm to hold the carrier block UP or may not drive the carrier block back down. DO NOT run this spring lose. Some back the screw off to make the rifle run lighter. BAD JOSS.
The side springs installed by the factory do NOT fit the frame. They need to be "refined" at the rear radius and when correctly fitted, can be run considerably lighter than stock.
If you have not disassembled the rifle yet, getting those lever spring screws out is going to be fun (NOT). Be prepared to replace the screws. When the springs don't fit correctly, you will strip the threads on the screws before you can get the spring to fit flat to the frame.
Coffinmaker