So far, Crane has put 30,400 rounds of M855A1 through three M4A1s equipped with 14.5″ cold hammer forged barrels and a mid-gas system with a gas block approximately 9.8″ from the bolt face.
They stated SOF M4A1s normally start to see accuracy degradation at around 6,000 rounds. But during testing of the mid-gas system, they’d hit 12,600 and still hadn’t seen any changes.
They also have only broken one bolt so far in testing, although I don’t think they’re ready to attribute the improved bolt performance to the mid-gas system.
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With this mid-gas system they are getting 5 MOA groups while the standard is 7 MOA.
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Interestingly, USSOCOM tests accuracy differently than most others. They fire 10 rounds suppressed and another 10 rounds unsuppressed. They measure the extremes of the spread of impacts, rather than their closest points. Then, they do it again two more times and average the results to determine accuracy.
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For high temperature testing, carbine-length weapons had 576.0 mean rounds between failures (MRBF) compared to 836.1 MRBF for ambient temperature testing and mid-length weapons had 2800 MRBF compared to 1993.8 MRBF for ambient temperature testing.
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They stated SOF M4A1s normally start to see accuracy degradation at around 6,000 rounds. But during testing of the mid-gas system, they’d hit 12,600 and still hadn’t seen any changes.
They also have only broken one bolt so far in testing, although I don’t think they’re ready to attribute the improved bolt performance to the mid-gas system.
...
With this mid-gas system they are getting 5 MOA groups while the standard is 7 MOA.
...
Interestingly, USSOCOM tests accuracy differently than most others. They fire 10 rounds suppressed and another 10 rounds unsuppressed. They measure the extremes of the spread of impacts, rather than their closest points. Then, they do it again two more times and average the results to determine accuracy.
...
For high temperature testing, carbine-length weapons had 576.0 mean rounds between failures (MRBF) compared to 836.1 MRBF for ambient temperature testing and mid-length weapons had 2800 MRBF compared to 1993.8 MRBF for ambient temperature testing.
Переводить сейчас времени нет, извините.
ИСТОЧНИК