Clutching and releasing breech spring tension

[qwarty]

описание башни БМП (точнее люльки)
The cradle accommodates the primary weapon and the secondary weapon carriage. In the cradle all controls necessary for the remote control of the primary weapon are mounted. These are:
• Clutching and releasing breech spring tension,
• Locking and unlocking,
• Ammunition alternating or belt feeder in middle position,
• Firing.

[mahavishnu]

А свой вариант перевода Вы не хотите предложить?

[Jimmy]

Сжатие и разжимание пружины казенной части орудия.

[Jimmy]

_Сжимание_ и разжимание )