u/HaloFrontier

Hello! Got just 30 rounds through my RDB and discovered two broken springs. I shot it with the gas valve "as it came" straight out of the box, fine, and then a few days later to zero an optic with the gas settings set "halfway" with two clicks more for reliability. The gun failed to cycle with 62 grain until I dialed the gas back up, and then the next thing I ran into was frequent light primer strikes (every 3-4 rounds).

I cleaned and inspected the gun afterwards which led me to discover two broken springs. The firing pin spring (Part #309) was in 3 pieces, which blocked the firing pin from extending fully into the chamber every now and then. This was a good discovery, and Keltec is sending me a firing pin repair kit.

The other surprise was this Action Spring (Part #316). It looks like the last loop of spring broke from stress or an unlucky manufacturing defect. This spring is firmly secured somehow to the Bolt Carrier Weldment (Part #322). I later learned that the rod it's connected to, the Action Spring Rod Weldment (Part #319), is supposed to be remain with the Bolt Carrier Weldment assembly as one unit when field stripping the gun. I disassembled and cleaned the gun the day I got it, but I was probably too inexperienced with the RDB platform to recognize this separation as an oddity.

Keltec customer service says my gun was manufactured in 2024 and can be ran with or without a replacement firing pin spring. (The issue with bolt slam-firing induced negligent discharges was fixed about 7 years ago with a sear redesign). However, for the Action Spring, the tech told me the spring is welded/retained(?) to the rod and not serviceable by customers. Sigh. I have a few questions for the community since I couldn't find any discussion on this online:

Has anyone else experienced this spring failure?
Are aftermarket replacement springs available?
Does anyone know how to replace it ourselves? I hate the idea of sending it back to Keltec for warranty repair after I just got it.

I'm not a spring engineer but I suspect the failure region is the area of highest stress in the coil since it transitions from a slanted coil to a radial plane, perpendicular to the axis of the rod it's tightly wound to.

I'm hoping I just got unlucky with these two springs, but so far Keltec's reputation is proving to be accurate despite my excitement for the gun. Thanks for the help in advanced!

I just bought a Hughes Precision 0.7" barrel extension for roughly $25 after reading BlowBack9's guide and seeing that its a quality piece we can use for extending a barrel and attaching a suppressor.

I'm trying to pair it with a Rugged Tri-lug Muzzle Device, which comes with the industry standard 0.625" deep threads. Because the Hughes extension only has 0.5" threads, there's now a 0.125" internal gap inside my barrel.

Not sure if that is completely harmless or if it affects shooting performance at all. I suspect it would do something to the flow of gasses as they exit the barrel and come upon a break in the smooth barrel wall. I don't plan on ever removing the barrel extension or muzzle device so I don't care about carbon build up on the threads.

I see a couple options:

Install my Hughes Precision extension now and forget about it.
Return the Hughes Precision extension and buy the Kaw Valley Precision 0.75" extension, which comes with the full 0.625" length threads. Sigh, I wish I had invested in this option first.

I'm a little irked I didn't notice the Hughes threads were short. Their customer service was not helpful at all and was giving me incorect information about the width of the wrench flats too, so I had to buy a NEW speciality 9/16" wrench just to be able to install their extension. In contrast, the KVP has ultra wide wrench flats and I wouldn't have needed to buy extra tools.

KVP is $30 plus $10 shipping and Hughes was $22 with $3 shipping, so I tried to save myself $15. Ended up needing to buy that $10 ultra thin 9/16" wrench. So its nearly a wash. Now I'm thinking I should try and return the Hughes and the wrench and buy the KVP to not worry about all this, but Hughes will charge me a 25% restocking fee (~$5?).

Should I stop worrying about trying to save a nickel here and just get the KVP to do the job right? Or does the little gap inside the muzzle device even matter and I should call it a day with what I already got?

Thanks in advance!

RDB Recoil Action Spring and Firing Pin Spring Failures

Gap inside muzzle device OK?