KingArms/WA M4 GBBR Cycling Problems
 

Hi ASC,

I just bought a King Arms M7A1 with an Inokatsu bolt and carrier that was tested and it worked (gave it a test dry fire a few times when we met up). Immediately after, I went out to buy a few extra magazines (G&P Magpul PMAGs) for the gun as well as several other accessories for the gun (UBR Stock, MBUS, AFG, and G&P Anti-reversal Links).

When I installed the anti-reversal links, the hammer came out and I had to reinstall everything back (hammer, trigger assembly, and selector) into the lower receiver. I believe I followed all steps properly as I had a manual to follow with. All parts were cleaned and relubed with silicon oil.

After installing everything, I gave it a test shot. I put one of the PMAGs in the gun, pull the charging handle, switch to semi, and pull the trigger. First shot comes out perfectly - but I was unable to pull the trigger for a second shot. Doing the same with a Prowin V2 magazine.. the gun failed to shoot at all (without any gas shot out from the magazine). I know the magazine has no problems as I have shot from it before and it has no leaks.

The only items I have modified that can affect the mechanics are the UBR stock (and buffer tube) and the anti-reversal links. I have reversed both of these modifications, but the gun is still observing the same problems.

Ideas?

I've said this many times in threads, but I'll re-iterate here: Silicone oil is NOT a viable lubricant! It has ONE main purpose: to keep o-rings from drying out. Beyond that, its lubrication properties actually suck big salty ones, and it makes a huge mess because of how much it creeps.

As for your problem, I'm thinking a part having to do with the sear, hammer, or full auto lock wasn't installed properly.

I'm trying to reverse the UBR stock, fearing it has something to do with the bolt not being able to fully retract into the buffer tube.. but the UBR stock is stuck. I can't get the UBR stock off the buffer tube for some reason even though it's supposed to just slip off. Something is holding it down or its caught on something.

Any ideas?

The rear screw holding it to the buffer tube?

Yeah, that's the only thing that should be holding it down. I've taken it off but the stock is still stuck on. It's weird.

I fixed the gun already, turns out that I just needed to adjust the buffers I was using since the tube was a different length, causing the spring to be probably too strong.