Abstract: An explosive primer designed for use with a fuse cord and an initiating device. The primer consists of a container, which holds the explosive, and a cap received on the open end of the container. The container has two lateral opposing cord tunnels which run the length of the container. The cord tunnels protect the fuse cord on the inside of the primer. The cap has two apertures which align with cord tunnels in the container. The cap has capwell for receiving the detonator. The capwell is pierceable so that a detonator can be inserted through the capwell and embedded directly in the explosive composition inside the container. In addition, the primer contains grooves in the bottom of the container and in the cap. The grooves communicate with the apertures and the recess in the cap and the cord tunnels to create a continuous conduit so that a fuse cord can be threaded therethrough to secure the cord to the primer and selectively position the primer in a borehole at the blast site.