Parts separating two pressure chambers, a corrosion allowance shall be provided on (strikethrough: either) each side of the parts.
两个压力室的分隔部件，应对部件的的每侧提供一个腐蚀余度。
英语百科
Chamber pressure
Chamber pressure (firearms) is the pressure exerted by a cartridge case's outside walls on the inside of a firearm's chamber when the cartridge is fired. It is generally expressed in PSI (pounds per square inch) or copper units of pressure.