RDB Troubleshooting Guide

Discussion in 'RDB Bullpup Rifle' started by Liberty4Ever, May 8, 2020.

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  1. Liberty4Ever

    Liberty4Ever Moderator Moderator Supporter

    May 19, 2006
    Lexington KY
    KTOG's RDB forum has had fairly regular threads requesting help with a malfunctioning RDB. The typical scenario is someone with a new RDB who had a bad first range trip. After a very similar community assisted KTOG troubleshooting session, the problem is resolved. Often, it was nothing more than a gas setting that had been misadjusted after the RDB had shipped but usually before the owner took possession. To get new RDB owners their answers sooner and to avoid a lot of repetitive typing, this troubleshooting guide has been created by the KTOG RDB enthusiasts and curated into a single troubleshooting guide. As new issues are resolved, this guide will grow, so if your answer isn't here, please start a new thread and post your question. Let us know that you've been through the guide so we aren't offering the old solutions to your new problem.

    SAFETY FIRST:

    The RDB is unlike most traditional firearms. The bullpup design has a number of advantages, but it makes it more difficult to determine if the chamber is loaded. Always verify that the magazine is removed and the chamber and Ejection Chute (part #355) are empty. The chamber can be difficult to see on the RDB. A flashlight can help. After visually determining the chamber is empty, verify the chamber is empty by poking your finger into the open chamber to feel that it's empty. Do not release the bolt when your finger is in the chamber.

    A malfunctioning firearm is frustrating and it's human nature to stop thinking and apply a brute force attack when we're frustrated. That could break your new RDB, but much more importantly, your haste could result in a negligent discharge that kills someone. If you're frustrated, take a break. When you're calm, your troubleshooting will be much more effective and much safer.

    Most of us won't want to spend valuable range time diagnosing a misbehaving new gun, so the troubleshooting will be postponed until we're home. That's more conducive to an unhurried troubleshooting session that is safer and more productive, but it can be tempting to test the cycling with live ammo at home. DON'T. Even if you do everything else correctly and the firearm should not have fired a round, you're troubleshooting a firearm that's known not to be operating properly, so whatever is causing the malfunction could cause the firearm to fire when it shouldn't. Either use snap caps or dummy rounds, or return to the range equipped with a better understanding of your new RDB and a plan to troubleshoot with live ammunition in a safe environment.


    1) Gas System Problems Or Mechanical Problems?

    If your RDB isn't cycling properly, try manually cycling the rifle with a dummy round. If the rifle loads, ejects, and strips the next round by hand, then the extractor and ejector are probably not damaged and are operating properly. There can be a big difference between manual cycling and dynamic operation when firing live ammunition, but this test could help eliminate some gross mechanical problems before troubleshooting the gas system when the problem is a broken extractor.

    The manual cycling test can be done with live ammunition, but only at the range, with the RDB pointed downrange, and with all four rules of firearms safety strictly observed.


    2) Incorrect Gas Setting

    This can cause a number of different problems - mangled cases, misfeeds, failure to eject, failure to feed, etc. The gas setting was adjusted at the factory to a value that should probably work with the ammo you're using, but even on a new RDB, someone may have randomly twisted the gas adjustment knob at the gun store. If you Read The Fine Manual, Kel-Tec describes the gas setting adjustment procedure. The KTOG procedure is very similar but is a bit more methodical because it's designed to avoid frustrating jams if the RDB has some undiagnosed mechanical problem

    You will be loading one round at a time into the magazine and adjusting the gas setting so the RDB locks back reliably on an empty magazine. Rotate the Gas Adjust (part #151) clockwise to close, then counterclockwise 10 clicks. Fire one round and load one round into the empty magazine. Close the Gas Adjust one click until the bolt locks back on the empty magazine. Then load 2 rounds into the magazine. It should fire the first, eject the empty brass and load the second round. If it does that without jamming, load 5 rounds and repeat. For more reliable operation, close the Gas Adjust one additional click in the positive direction (clockwise when viewing the RDB from the muzzle end).

    Troubleshooting is much easier when you understand how the RDB operates. The Gas Adjust is a bleed valve. Closing the Gas Adjust by rotating clockwise (the plus direction) allows less gas to vent therefore increasing the pressure going to the Piston (#143) that provides the force needed to cycle the RDB to eject the brass and move the bolt to the rear where it can strip another round from the magazine and chamber it. Opening the regulator by rotating the Gas Adjust in the minus direction allows more gas to bleed to atmosphere resulting in less pressure going to the piston. Under-gassing the rifle could result in the spent case not being ejected because the bolt carrier with empty case must travel past the loaded magazine.

    Over gassing can cause issues such as having a cyclic speed that's too fast for the ejector to drop the empty case before the carrier again starts its forward travel. Over-gassing also causes needless wear to the RDB and the recoil characteristics are less pleasant for the shooter.

    It's important to find the right sweet spot based on the ammunition. This is not a set and forget system in that changing loads may result in the need to tweak the gas occasionally. Less friction in the RDB after break-in may result in the need to open the Gas Adjust a click or two in the minus direction to bleed a little more gas that's no longer needed after break-in.


    3) Service and Repair Parts In Canada

    Vault Distribution in Vancouver is Kel-Tec's Canadian distributor and they are the source for repairs, service and parts for Canadian owners.

    http://www.vaultdistribution.net
     
    dazed, The Sleep, RC-78x and 9 others like this.
  2. Liberty4Ever

    Liberty4Ever Moderator Moderator Supporter

    May 19, 2006
    Lexington KY
    Kel-Tec oracle Chad describes how to adjust the gas system:

     
    dazed likes this.

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