Knoxx sidewinder converted Mossberg 500


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

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • That bitch is hard as hell

  • Matt

    I’ve got one of these and I gotta say, It’s bad ass! It’s nice to just drop the drum and smack another one in quickly! Just wish it was a little easier to find more mags.

  • Rick

    I’ve got a mossberg 500 with the sidewinder kit, one 10 round and one 5 round magazine, vented heat shield, knoxx spec-ops stock, all in a rolling foam lined hardcase with wheels.

    Any idea what i could expect to sell it for? I’m looking to pick up an antique English over-under and figure I need to sell part of my collection to get another.

  • Rick, you may regret selling it in the future!

    I would search and see what similar shotguns are selling for.

  • Ed Hilfiker

    Need asmbly directions for sidewinder to moss.500.Thanks Ed

  • Jamie


    Whats up man? I would like to buy the knoxx sidewinder conversion kit or the hole nine yards….if your selling it! Thanks for your time..happy holidays!


  • jon

    still looking for this conversion kit. i understand knoxx discontinued this item, but i don’t know why. seems like alot of poeple looking for it. would make sense to me for someone to start remaking of modify the old one and manufacter something new. anyway if anyone wants to sell or know someone who is selling i am interested. contact me 760-803-9686….jon

  • Amir

    Just purchased sidewinder kit for the Mossverg 590 but need some type of adapter if anyone knows where I can purchase one e-mail me please.


    i have the rolling thunder….. and iam looking for a dum kit to.. someone email me info….

  • ashton

    Hey I have the mossberg 500 with LED, 6 round side saddel, vented heat shield ,and folding stock. The sidewinder would be a nice tuch. How much did u buy yours for and do they no longer sell them at all or are they just hard to find.

    • ashton, try gunbroker.

  • cody

    i have a knoxx sidewinder kit and 2 mags i am wanting to sell feel free to email me at cody_n_alabama [a t] yahoo [dot] com

  • Matt Miller

    They are very hard to find. Gunbroker has ONE and it’s going for $650.

  • glen garretson

    im looking forthe knox kit someone please sell me one email me at thanks

  • Dakota Wills

    Anyone wants to sell a sind winder or any siga gear contact me at or 907-440-7008

  • I will buy one at any REASONABLE price. For a 500A. What mods are necessary?

  • thekid

    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.