Abstract: A self-aligning tool for inserting percussion caps on firing nipples comprising a central hub with radially spaced apart spokes that each form an integral arm that terminates in a distal hand for temporarily securing the percussion cap until insertion. Each elongated arm comprises at least one storage hole for storing additional percussion caps. Each distal hand comprises at least one holder for temporarily receiving and retaining the percussion cap. Each holder defines a circular hole into which the cap is inserted for retention. Each holder comprises a periphery defining arcuate outer and inner lips separated by an elongated lateral slot. During the insertion process, the user aligns the percussion cap with the nipple by inserting the arcuate holder lips into the exposed breech. When the lips abut the interior walls of the bore, the cap is also aligned with the nipple. The user then presses the percussion cap firmly against the nipple until it is seated.