1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

AR Buffer Tube Question

Discussion in 'Gunsmithing and Repairs' started by joebogey, Jan 23, 2013.

  1. joebogey

    joebogey Well-Known Member

    First off, I'm fairly new to ARs.
    My daughter wanted an AR for Christmas, so I purchased one of the New Frontier polymer lowers. She decided she wanted pink furniture so I figured that as long as it kept her interested, I'd get the pink. :barf:

    The stock I got required a mil spec buffer tube which I found used on line.
    Now for my question..... when I installed the mil spec tube it doesn't come forward enough to hold the buffer and spring inside the tube because I can't go another full turn without covering the little spring loaded retaining pin that holds the buffer and spring in place. Am I correct in assuming that using a dremel to make a small notch in the end of the tube will allow me to come one more full turn and still hold the retaining pin in place?
    The commercial tube did have a small indentation in the end of the tube which I take it was for that same reason.
    Hope this makes a small amount of sense to you.
    Thanks for reading my babble. :eek:
  2. rcmodel

    rcmodel Member in memoriam

    Yes, you can notch the tube.

    Some tubes come already notched, some don't.

  3. joebogey

    joebogey Well-Known Member

    Thank You Sir.
    I appreciate the reply.
  4. AlexanderA

    AlexanderA Well-Known Member

    Either the buffer tube or the lower receiver is out of spec. The tube is supposed to screw in far enough to cover the shoulder of the buffer retaining pin, while allowing the center nub of the pin to protrude. (There's almost 1/16" of fore-and-aft leeway here.) What you're supposed to be able to do is screw in the buffer tube until it overrides the shoulder of the buffer retainer pin and contacts the pin's center nub, then back it out until the stock is properly oriented. Then it's locked in place by tightening the castle nut against the receiver end plate. You shouldn't have to grind on the buffer tube. (This is assuming that it's a telescoping stock we're talking about.)
  5. joebogey

    joebogey Well-Known Member

    The tube is plenty long enough as are the threads. But if I go in far enough to cover the edge of the pin, it puts the adjustable stock upside down. By going half a turn more either way, I'm either too short or too long.
    By putting a small slot in the end of the tube where it rides on the pin, I hope to gain half a turn more which will put the stock back where it belongs as well as cover the edge of the pin.
    The commercial tube had a slot in the same way.
  6. AlexanderA

    AlexanderA Well-Known Member

    I suppose it could be done that way, but the original design doesn't call for such individual fitting. You said the buffer tube was "mil spec." But was it an actual GI buffer or was it aftermarket? Maybe the fault was in the polymer lower receiver?
  7. browneu

    browneu Well-Known Member

    I'm sure you already know this but you'll need the castle nut whether you decide to notch the tube or leave it be.

    Sent from my SGH-T999 using Tapatalk 2
  8. 1911 guy

    1911 guy Well-Known Member

    I'm no expert on the collapsible stocks, but i thought the buffer tube was threaded in to retain the buffer retainer and then secured with the castle nut? The couple collapsibles I've done seemed to never bottom out like an A2 tube does.
  9. justice06rr

    justice06rr Well-Known Member

    That is your answer there.

    Since that original commercial tube had a notch, it means that a milspec tube without a notch will go over too far covering the buffer retaining pin. So YES, you can make that notch yourself to remedy the issue.

    What I'm assuming is that these polymer lowers are threaded a little different than standard aluminum lowers. I have the ATI/Omni polymer lower and it also has the notch on the commercial buffer tube.

Share This Page