The Rival Knockout comes with a strange shaped priming handle on the bottom of the grip. This handle can be removed with two screws revealing a hole in the bottom of the priming bar large enough for a M5 bolt. I've designed some spacers/handles to both keep the bolt centered on the priming bar and increase the diameter of the bolt, where your fingers grip it, for comfort.

What you'll need: M5x45mm bolt M5 nut

This modification requires no cutting/drilling. Simply unbolt the stock handle and bolt on an M5 bolt with my little handles installed.

December 19 update: Added display stand. The T handle sits in the stand and holds your blaster upright.