As more and more people have been getting the matrix, there have been more and more problems with fsdo and shootdown. I know for a while I had these two problems, but there are solutions. Here are the basic ways to cure it.
1. Lube your matrix right! You must properly lube your bolt assembly or you are going to have problems. Too little lube and the bolt will stick, and too much lube will cause much of the same problem. When you lube your assembly, put a thin coat on all the o-rings (more so on the stem o-rings), and a very thin coat on the front of the bolt itself.
2. Types of lube. For a while, I was using cinnamon crease and having problems with it. It seemed pretty sticky so I tried differednt lubes and found that matrix muck works great for me. Some other great lubes you can use are dow 33, motion potion, or even home-made matrix muck (dow 33/55 and paintball gun oil). Don't give up on your matrix! Try different types of lubes.
3. Quality of o-rings. The shape your o-rings are in can really affect your performance. If they are too old/swelled, they can cause drag on your bolt, which can cause stickiness. Also, if they are not exactly the right size/make, they can cause problems. Buy the types of o-ring kits reccomended specifically for your bolt kit, and you shouldn't have any problems.
4. Batteries. As simple as this. If your gun battery is low, FSDO can occur. Keep track of your battery life.
5. LPR settings. You must correctly set your lpr to not have FSDO/shootdown. Here's how: turn your lpr all the way in. Now, set your inline reg to your desired velocity. Begin to back your lpr out until you see a drop in velocity, and give it another half turn.
If your LPR is too low, you will experience mad fsdo. Give it small cranks if you still experience minor fsdo even after setting it as described.
6. ABS (anti-bolt stick). This is a mod that gen-e and dye perform on matrix boards. It basically increases the dwell for the first shot after a certain amount of time (usually 8 seconds). This should be your last resort fix as it will take the most time. Not all matrices need ABS; some do.
Hopefully this helped to anyone that had fsdo and shootdown problems. If I can think of anything else that will contribute to this thread, I'll post it. Otherwise, anyone else can feel free to add to it because I feel it would be a valuable sticky