The SAP Two Round Holder Magnum in Coyote allows for quick access to two additional rounds, fitting case bodies 0.550" to 0.800" in diameter.
This holder can be attached to nearly any rifle with the provided industrial-strength Velcro, but the surface must be prepped with 91% rubbing alcohol and dried completely.
Short Action Precision Inc manufactures this accessory, designed for convenience and efficiency, categorized under Extra Round Holders.