Power Bumpers

[Matt H.]

Originally Posted by Mr. Freeman

I think all the regulators vent if the pressure in the downstream line increases above whatever they're set to. This should prevent the pressure in any pistons from increasing above the safe limit.

This may be correct however pressure changes are not instantaneous. If a cylinder is impacted there will be a local increase in pressure within the cylinder meaning the cylinder will be exposed to high pressures before the regulator can vent the pressure.
Consider the traditional bike pump (which is just a cylinder). Even when pumping nothing (i.e. moving air around) a local pressure region developes inside the pump making pumping more difficult--If you were to hit the handle with a hammer a very high pressure region would develope before it could be vented by the nozzle.