• Tapered castle nut to seat and seal itself into place without the need of staking the end plate
  • No ratcheting, no set screws, no backing out and no failures
  • Quick Detach Socket - 360º rotational locking interface
  • Available in anodized black, blue, flat dark earth, gold, grey, and red finish


  • Material: 7075-T6 Aluminum
  • Finish: Anodized Black, Blue, Flat Dark Earth, Gold, Grey, or Red
  • Weight:
    • Endplate: 0.42 oz.
    • Castle Nut: 0.14 oz.


  • AR-15 and AR-10

**Anodized areas that touch between the end plate and castle nut will have expected minor scratches from torquing of the castle nut.

**Due to various factors that take place during the anodization process, the color lines from batch to batch of a certain product may vary.


  • 1x Fortis Lightweight Enhanced K1 End Plate
  • 1x Fortis K1 Tapered Castle Nut


How many times have you went to remove the castle nut on your AR, slipped and scuffed it? I know, if it's staked properly, it can be hard to break loose and things happen. It's just a little thing, you can barely see it, but you know it's there. When you change to a Fortis K1 Castle nut locking system you will never have to mess with staking that thing again.

There Is Another Way to Skin A Cat

The revolutionary design of the Fortis tapered castle nut is made to work with the Fortis LE End Plate. Together they securely attach your buffer tube without having to stake anything in place. The outer circumference of the tapered castle nut wedges itself into the tapered inner surface of the Fortis LE End Plate to create a perfect bond that virtually guarantees it won't back off. Of course, you are still going to want to use an armorers wrench to torque down the Fortis K1 Castle nut, but it will stay tight without having to stake it in place.

One Less Step When Installing the Fortis K1 Castle Nut

Properly staking a castle nut isn't really that big of a deal, but sometimes breaking it loose can be. I worked on a friend's AR once, he had used Locktite on the castle nut on top of staking it. It took heat and some bad words to get it loose. Well, the Fortis LE End Plate combined with the fitted, tapered castle nut locks in tight and comes off easily, heat and bad words are not requried. Additionally, Fortis machined an attachment point for a QD sling swivel into the enhanced endplate. This cutting-edge convenience should be on your gun today.

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Reviews (10)

  • Great Product

    Posted by JD on 27th Feb 2022

    The end plate with K1 system is a professionally machines addition for your AR that is as described and order process and shipping was very timely and the item was priced at a fair market price.

  • Not worth your money!

    Posted by Christopher Jurkowski on 23rd Feb 2021

    I received the castle nut and end plate and it looked very promising. The moment I touched it with an armorer's wrench, the finish started coming off. The castle nut looks like hot garbage now and I am unable to replace just the nut because you have to buy the full assembly. Do yourself a favor and don't waste your money on this. For over $40, it's not worth it. I emailed Fortis a couple times. No response. I am very dissapointed. You shouldn't pay good money for junk. Many better options out there. Fortis doesn't stand behind their products.

  • Fortis Quality

    Posted by William Ferrel on 18th Feb 2021

    I have purchased a few fortis parts for my builds. The quality is consistently high. Never machining Mark's or bad anodizing. Tolerances are consistent and uniform. This castle nut and end plate is no exception. The tapered end plate helps lock the castlenut in nicely without having to over torque. Just take it slow and steady on install then one last good steady pressure and its locked in. I've had no issues and would reccomend this product.

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