Issue 01
Finding the trigger signal
With a simple electric trigger, connect the white signal cable to the output (normally-off) side of the trigger. FCUs and MOSFET boards have many advantages and are recommended, but finding a suitable trigger signal on them is harder.
Use Test Mode
In Test Mode the XM203 is not live and will not fire. Instead, the LED flashes orange every time a trigger signal is received, so you can confirm the white signal cable is in the right place before going live.
The white signal cable is an input only and does not output a voltage. It needs more than 2 VDC to activate, and detects voltage rather than current.
FCUs with active braking or motor alignment can activate the XM203 on power-up. Enable Start in Silent Mode so the unit only goes live when you tap the up or down key. See the firmware guide for details.
Issue 02
Gas types and filling
Use
MAPP gas (recommended)
Propane
Do not use
Butane
Liquid fuels
Any gas not listed
MAPP is preferred, especially in cold conditions (below 5 °C), because it does not turn to liquid and upset the gas-to-air ratio.
Not all fill adaptors are equal
- Efficient liquid transfer is what gives you a full charge. If you’re only getting a limited number of shots, try a different adaptor.
- Make sure there’s enough liquid gas in the bottle — as it empties, less liquid transfers and you get fewer shots.
- Temperature also affects transfer from the bottle to the XM203 tank.
Issue 03
Gas adjustment
Understanding the GAS ADJ dial is the single most important part of getting the best from the XM203. Watch the video to see how the setting affects performance.
Every unit is different. A setting of 5 does not mean 100% efficiency — adjust for the conditions and your unit, and don’t compare settings between units.
Issue 04
Lubrication and cleaning
Before each use, oil or lubricate the indicated areas. Skipping this reduces performance and can eventually damage the rear firing seal.
Standard silicone oil burns off quickly. It can be used on the firing sleeve and cylinder, but use a heavier-duty oil on the rear seal. RDX recommends Breakthrough Battle Born High-Purity Oil. Any oil you use must be non-flammable, non-toxic and compatible with silicone and NBR (nitrile rubber) seals and O-rings.
Regularly check the oiled areas and clean off dirt and grime. The system tolerates significant dust and debris, but periodic inspection protects the rear seal and keeps the unit reliable.
