Keystone Rebel:  The Krag magazine spring serves two functions - 1.  It bears against the magazine door, where it hinges, so that the door will stay open, when loading, and firmly snap and stay shut, when closed.  2.  The spring also has a dog-leg at one end which engages a cam and powers the follower assembly to feed cartridges.  The spring is arched.  When properly assembled and in place, the spring 'arches' outward and the middle of the spring touches the middle of the door hinge.  The 'dog-leg' tip of the spring touches the machined cut of the follower cam.  The easiest way to check spring function is to take the action out of the stock and remove the left side-plate.  If the magazine door is shut, the follower will be visible at the side-plate opening and can be pushed inward against spring pressure.  When the magazine door is opened, the follower assembly will fold up into the hollow interior of the magazine door.  The engagement of the spring tip can be checked by rotating the magazine door hinge pin so that the small flat spring/cover, attached to the front of the hinge pin, lifts out of its recess.  The cam and spring tip engagement can then be viewed.  It is possible to assemble the 'arched' flat spring incorrectly (Dog-leg tip behind cam or arch projecting inward, instead of outward) and jam the follower function.  Also, the spring could be broke and need replacement.

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