Knoxx sidewinder converted Mossberg 500

Steve Johnson
by Steve Johnson

The sidewinder is an interesting thing. It’s a magazine feed conversion kit available for the Mossberg 500 and 590; along with a system of six round box, or 10 round drum magazines. This allows for rapid reload, and rapid changes of ammunition type, which I appreciate; as well as greater magazine capacity in the shortest possible barrel length (no long mag tube extensions).

I should say it WAS available; last month Knoxx took it off the market, because they couldnt manufacture it economically for the quality they wanted; and belive me that quality is very high. Although the finish on the kit leaves much to be desired, it is INCREDIBLY tough. There are videos on the Knoxx site of the sidewinder mags being run over by pickup trucks, and thrown 30 feet onto the ground with no more damage than scratches.

More here and here

Hat Tip: GunPorn

Steve Johnson
Steve Johnson

I founded TFB in 2007 and over 10 years worked tirelessly, with the help of my team, to build it up into the largest gun blog online. I retired as Editor in Chief in 2017. During my decade at TFB I was fortunate to work with the most amazing talented writers and genuinely good people!

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  • Thekid Thekid on Feb 11, 2013

    looking for a sidewinder kit for sale for a mossberg 500 or for a 88 contact me at


    Waited nearly 3 years after paying for first gen sidewinder kits, Another year for second generation replacements. Both were extremely poor feeding on mossburg 500 shotguns.GOT NOTHING BUT LIES FROM MANUFACTURER. Have since removed kits for reliability and returned to extended tube mags with no issues. I have saiga drum fed 12 with no issues also. Even my old High standard model 10 shotguns work better. Put your money into better options. Kel-tec is making a copy of the old neostead dual mag pump 12. Seems promising.