Buffer tube but / Castle but?? Slid right off..

Discussion in 'Sub9 and Sub2000 Rifles' started by JRager, May 22, 2020.

  1. JRager

    JRager Member

    Jan 1, 2018

    So this happened while I about to add a buffer tube cover. This hasn't been fired. Was a replacement for my Gen 1 that cracked in half after about 2000 rounds...

    It slid right off almost no effort and will not tighten. No threads that I can see... So what's up with this?
  2. ColdFire0200

    ColdFire0200 Well-Known Member

    Apr 19, 2020

  3. Saltlick

    Saltlick Well-Known Member

    Apr 22, 2020
    mine had the SAME problem, after less than 100 rounds the thing just slid right off. i ordered a new collar from KelTec, it was like $5 or something. the threads on the stock collar were all ate up. the new collar has arrived, but my weapon is still in pieces as i am waiting on just 2 more parts from MCARBO to get here before i will reassemble it. so i havent put on the new collar though i assume with the good threads and Loctite 380 Black Max it will be fine.
  4. SixFootCow

    SixFootCow Member

    Oct 1, 2019
    You bought a 6 notch castle nut which is gen2. A gen1 only has 4 notches and has a different inside diameter of threads. Looks like you either bought the wrong one or they sent you the wrong one. Not saying you will not still need thread lock though but at least it should fit better with the right nut.
  5. JRager

    JRager Member

    Jan 1, 2018
    Sorry should have clarified , this Gen 2 was sent to me by Keltec to replace a Gen 1 that cracked in half, and has not been fired yet.
    SixFootCow likes this.
  6. Gone Fishing

    Gone Fishing Member

    Dec 6, 2018
    You can take a new or used castle nut and machine or file a slot in it. If you are careful and take your time, you can do it by hand. Then, after you reassemble, you can use a single or double point sling mount to clamp the castle nut in place.
  7. Dubar

    Dubar Well-Known Member

    Oct 5, 2018
    Is the castle nut polymer? Mine is and as far as I can tell serves no useful purpose except to hide the area like a piece of door trim. It sure wouldn't keep anything in place. I have since put a sling mount on mine (like in the 2nd photo which is not mine) and it keeps the castle nut from moving:



    UZIFORME Member

    Dec 1, 2004
    There is no threads, it's not a nut, it's just a slip on cap that glues in place.
  9. Moondog

    Moondog Member

    Apr 29, 2018
    I put more epoxy glue but over time, it got loose again. Now I just wrap some electrical tape immediately behind the "nut", thick enough that it keeps the "nut" from sliding further back on the stock-tube.

    Last edited: Aug 26, 2020
  10. Saltlick

    Saltlick Well-Known Member

    Apr 22, 2020
    LocTite 380 BlackMax is your friend; add the armorers wrench from MCARBO!! no need for electrical tape!