Operating Systems

Long Recoil

As with short recoil operated systems, in long recoil the bolt and barrel also recoil freely. In long recoil instead of the barrel stopping relatively early, bolt and barrel recoil together until they reach the end of travel at the back of the receiver. Since the combined masses of the barrel and receiver are relatively large, these types of systems tend to have longer cycle times leading to slower, smoother operation.

In long recoil designs the bolt and barrel usually have independent return springs. Once they reach the rearward end of their extention, the bolt engages a catch and extraction begins. The barrel freely returns to its forward position, clearing the cartridge from the barrel's chamber and allowing it to eject. In closed bolt designs the bolt then moves forward chambering a fresh round, ready for the next shot.

Long recoil is often found in large naval guns or artillery pieces. In small arms it's quite rare, one notable exception being the Browning Automatic shotgun. One might wonder if allowing the barrel to move from shot to shot would be a detriment to precision. Apparently as long as the barrel is designed to return to position consistently (and actually does) this is not a problem.

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