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Problem with new M4 Bolt hangup


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I just got my new M4 assembled it and was cycling some rounds.


I noticed when the shell release lever (part #076J) is down showing the red circle, when I pull the bolt head open all the way back it just hangs there like it's stuck. I have to push on the bolt handle forward to get it to close again.


Is this normal? or is there something that needs lubing or breaking in so it doesn't hang up like this?



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I spoke to Customer Service. they said i should clean the heavy grease and break in with 100 rounds.


They said that when the m4 is fully loaded with one in the chamber the bolt carrier shoudln't get stuck open when you rack it back.


Anyone else have this issue?

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I recall experiencing that when I first got the M4 and tried to cycle dummy rounds. Somewhere between 1 and 2 boxes of standard field loads cured it. I doubt you have anything to be concerned about. I've noticed people have had to shoot alot more than I did to 'break in' the M4, but mine was a store display and may have been manually cycled a bit.

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  • 3 weeks later...

After about 100 rounds it still happens when i bull the bolt back manually. during the 100 rounds it hung up during shooting 1 time.


does replacing the recoil spring in the stock help? it seems like the boalt carrier doesnt' have enough force and gets caught up on the breech bolt latch (#019J).

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