MWS models from Marui or Secutor use the best system for a GBB (020’s subjective opinion; there may be some debate here, but this is our opinion), but it is still a gas-powered mechanism and needs a little more attention than an AEG. The good news is that keeping it in good shape does not require turning every Sunday into a workshop inspection either. 

1-CLEAN THE BARREL... BUT KEEP IT DRY

In a GBB, traces of silicone, dirt or residue inside the barrel can quickly affect accuracy. Use a cleaning rod with a clean, soft cloth, avoiding aggressive products. 
And remember something important: the hop-up rubber must remain clean and practically dry. Excess lubricant can cause it to lose grip on the BB and result in irregular trajectories. Tokyo Marui even warns that excess oil can temporarily destabilise hop-up performance. 

2- LUBRICATE IT, YES. DROWN IT IN SILICONE, NO.

The bolt needs to move smoothly, but that does not mean filling the inside with oil. Apply a minimal amount of lubricant compatible with seals and polymers to friction areas and pay particular attention to the movement of the bolt and nozzle. 
Avoid mineral oils such as CRC or similar products: Tokyo Marui specifically warns that they can damage certain parts. In an MWS, more lubricant does not mean better performance. 

3-MAGAZINES NEED MAINTENANCE TOO

You can have the perfect replica and ruin the game because of a magazine that leaks gas. Periodically check the valves and seals, especially if the magazines have been stored for a long time. 
If a small leak appears, the problem is often a dried-out seal or a valve that needs maintenance, rather than the magazine itself. Keeping the O-rings in good condition is considerably cheaper than starting to replace parts without knowing where the leak is coming from.

4-KEEP AN EYE ON THE NOZZLE AND BOLT

These are two of the hardest-working areas in any GBB. From time to time, disassemble the assembly and check that the nozzle moves freely, returns correctly and shows no cracks or abnormal wear. Do the same with the bolt's contact surfaces. 
There is no need to disassemble half the replica after every game. In fact, one of the strengths of the MWS system is its reliability. But a quick inspection allows you to detect a part that is starting to cause problems before it ends up breaking in the middle of a game.

5-DON'T CONFUSE COLD WEATHER WITH A MALFUNCTION

Before taking anything apart because your MWS starts cycling poorly, check the temperature of the magazine. The gas cools down with every shot and, the lower its temperature, the lower its performance. 
Tokyo Marui recommends checking the magazine temperature first when range decreases or irregular operation occurs. In winter, an MWS that starts running more slowly may be perfectly fine: it is simply reminding you that it is still a GBB.

The SECUTOR CENTURION MWS and Tokyo Marui MWS models do not need obsessive maintenance. They need the right maintenance: a clean barrel, just enough lubrication, well-maintained magazines and an occasional inspection of the moving assembly. Five minutes well spent can save you plenty of trouble later.