If your using an older version SGKv2 follow the steps (here)

Open the BP_MasterRangeWeapon open the ChamberChecks function and add the highlighte nodes shown in the image below.

Then copy the videos below.

Older SGK Version Steps

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Open the BP_MasterRangeWeapon then go to the Reloading collapsed node and add the highlighted node in the image below.

Then copy the video below.