I've been having a few problems lately with my Black Mamba from Volquartsen. The trigger wasn't resetting all the time and I was getting failures to fire. This stumped me so I took out the Accurizing Kit to see what was wrong.
I added a Tandemkross Victorry Trigger to the system. I ran about 50K rounds this way without a problem. When I put the gun back together, which normally takes me 15 minutes it would not fire at all. I reinstalled everything over a 3 hour period and still got stumped.
Someone lead me to replace the trigger plunger spring. They said the TK trigger wouldn't work with the VQ spring.
I gave it a try and replaced the spring with a stock one. First time out and the gun is running 100 % again.
I even treated to a new pair of grips from StonerCNC.com.