RDB-S - Collapsible Stock Won't Extend

Discussion in 'RDB Bullpup Rifle' started by Liberty4Ever, Nov 19, 2018.

  1. Liberty4Ever

    Liberty4Ever Moderator Moderator Supporter

    May 19, 2006
    Lexington KY
    I just picked up a new RDB-S today and it's such a cute little rifle. I'm loving it but my only complaint is that I couldn't extend the collapsible stock. I saw what I thought would be the stock release (it actually was) but that metal tab wouldn't move. I read the manual and learned that actually was the release and I looked at the exploded diagram to see how the mechanism operates. I verified that I was trying to use it the way it was designed to be used and it was stuck.

    I figured that something was bound when the RDB-S was "kinetically assembled" at Kel-Tec, or less likely, some rough handling in shipping had caused a problem. I disassembled the RDB-S into the four major assemblies and once apart, the collapsible butt stock repeatedly and reliably worked as it should without difficulty and without binding. I decided to reassemble it with the butt stock extended to prevent any possible binding that might occur during reassembly. After reassembly, the stock release lever was easy to manipulate and the stock could be easily collapsed in what seemed certain to be the way it was designed to work. Problem solved! Only nope. Once collapsed, the stock release once again wouldn't move and the stock was stuck in the collapsed position. Anyone else have this problem? Anyone got a solution?

    I'll probably disassemble it again and take a better look tomorrow to ensure that all of the relevant parts are there and they're in the correct position.
  2. Liberty4Ever

    Liberty4Ever Moderator Moderator Supporter

    May 19, 2006
    Lexington KY
    Problem solved. It was kind of a false alarm. Everything was assembled correctly but the sliding polymer portion of the butt stock is such a nice interference fit on the steel underneath that it was very difficult to slide. The problem was compounded by my initial assumption that the stock lock needs to be depressed to extend the stock. It doesn't, and in fact can't. I was also pulling out on the bottom of the butt stock, near the stock lock, and this caused additional binding between the plastic and steel parts. The stock is much easier to extend when I grab the molded serrations at the back of the butt stock and pull straight back, rather than pulling on the bottom of the butt stock.

    I lubed everything with synthetic gun oil to reduce the stiction between the polymer and steel and all is now well. I wouldn't want a loose fit between these parts because that would result in a wobbly and rattling butt stock, and that always seems cheap and it really aggravates me. In the extended or collapsed position, the RDB-S butt stock is rock solid, and that's worth a little more oomph during the deployment.

    The only thing I'd change is the manual. It says to push back on the stock lock when extending the butt stock, and that's not possible. That caused me to think something was mechanically wrong. The stock lock is only depressed to unlock the extended butt stock so it can be collapsed. To Kel-Tec's credit, the manual does show a red arrow indicating that the butt stock should be pulled straight back along the top. I still think that could be emphasized a bit more with a warning not to try pulling back on the bottom of the butt stock because that causes binding. A thin film of grease on these parts during assembly could have also made life a bit simpler.

    While I was doing the liquid overhaul, I took the opportunity to put some synthetic oil on the black oxide finish on the three assembly pins and that made the break down and reassembly significantly easier.

    I'm chocking all of this up to that wonderful Getting To Know You phase with a new gun.
    quince likes this.

  3. lee1000

    lee1000 Member

    May 11, 2017
    That's the first time I've ever heard of a rifle being referred to as cute
    Tacoma20023rd likes this.