Below are the rules for the construction of pneumatic parts/ weapons from the FRA.

9.7 Rating
All pneumatic components used with pressures greater than 50psi (3.4bar) must be rated/ tested to at least
The maximum pressure available in that part of the system, you may be required to provide documentation/certification to support this.

9.7.1 Custom Components
Custom made components, or parts operating above the suppliers maximum working pressure, must be
Independently tested and certified at 120% of the maximum system pressure available at that point.

I think the way it is written is un-ambiguous all pneumatic components,

Similar with custom components.

In my field as a gas engineer, if there is an incident I have to prove I am innocent to the authorities.
So let€™s say a custom made component failed and someone was injured, and later it was found the equipment did not fulfil the FRA build criteria would there insurance cover you?