An embolic implantation system configured to deliver an embolic implant intravascularly to a treatment site includes an elongated delivery tube to which the embolic implant is detachably attached by a flexible loop extending through a retaining ring or opening on the embolic implant and an elongated detachment member or pull wire extending through the delivery tube and flexible loop. The pull wire has a bump near its distal end that inhibits the pull wire from moving further distally when the bump presses distally against the flexible loop and/or retaining ring. The flexible loop and retaining ring thereby serve as a distal obstruction obstructing distal movement of the bump and thereby distal movement of the pull wire into the implant.