JBL, Magnum Hi (Open Muzzle) All Spearguns >>> Spearguns by JBL More details and ordering info. The Magnum 450 and the Magnum are designed for long range and heavy penetration where range is important and heavy penetration is required. User input on Magnum Hi (Open Muzzle) by JBL: Be the first to submit input on this product Submit Input: Your Name: Write or Paste Input here: Upload picture:      Review Guidelines