So you've been using your MK23 lovingly for a while, everything's great and you've not touched a thing. One day, you decide to squeeze off a couple of rounds only to find that your MK23 has contracted the deadly "Sticky Trigger" syndrome; leaving your trigger pulls in a locked back position that requires you to manual reset it to neutral after every shot.
(Sticky Trigger Example, provided by Graham Franks)
The "Sticky Trigger" can occur after making changes during an upgrade, but most commonly, it tends to happen out of the blue and often without much indication as to how or where in the pistol the issue originates from. This usually results in you, the user, pulling out all sorts of bits trying to cure the problem, from the hop up, to the barrel, to the feed lips, to the router. If the router was the last piece you tinkered with, you were certainly warmer to the most common cause of this issue (the other being the hop rubber holding the nozzle in place). Usually, either due to poor factory quality control or wear over time, the gas router in the magazine can slip up or down in it's slot within the magazine. In addition, its shape can also deform. Between the two of these issues, the position of the gas router can either be closer or further away from the the piston nozzle port (the bit that receives the gas from the gas router). When the router is further away from the nozzle, the amount of gas let in to the piston is reduced and movement of the nozzle through the router is reduced. When the router is closer to the nozzle, the amount of gas let in to the piston is increased and movement of the nozzle through the router is also increased.
As the nozzle and router get closer, more friction is applied whilst in contact with the rubber gas router - eventually the friction gets to the point where it can hold the nozzle in place and prevent it from returning to a neutral state; this neutral state is needed to allow the trigger mechanism to free up too and allow the gun to re-cycle. The solution So now we know our enemy, how do we defeat it?
Mark Sutherland, an admin in the MK23 Owners Group, stumbled across an innovative and cheap fix that completely solves the issue. Like most solutions, it involves the "fix-all" that is Teflon Tape.
Mark had the "Sticky Trigger" issue himself, and identified that the router was positioned too high in the magazine, so he took the direct approach and lowered it by shimming the router away from the nozzle. After removing the gas router from the magazine (instructions available here), he added several wraps of PTFE Teflon Sealant tape around the base of the upper part of the router. This acts as restrictive padding that compresses the gas router slightly and prevents the lip of the router from rising too high outside of the magazine. It's really an elegant solution that doesn't take very much explaining, the photos below really do the talking.
Simply add 1-2 layers to start with, reinstall the gas router, and test the trigger; add another layer if needed until the issue is resolved. That's all there is to it.
Thanks for the help Mark, relatively free solutions are always the best solutions!