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Posted: 3/9/2020 7:31:32 PM EDT
Got an M4 today, assembled per the instructions and the bolt only goes back about 3/4th of the way. If the barrel is taken out the bolt moves fine. I’m confused and so is my FFL

Anyone seen this before?
Link Posted: 3/9/2020 7:34:22 PM EDT
[#1]
Link Posted: 3/9/2020 7:43:06 PM EDT
[#2]
Hammer back when inserting the trigger group?
Link Posted: 3/9/2020 8:09:42 PM EDT
[#3]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Hammer back when inserting the trigger group?
View Quote
Yes
Link Posted: 3/10/2020 7:49:38 PM EDT
[#4]
Remove the trigger pack and see if the binding continues. It should give you a better view of what is happening with the barrel installed. This should help isolate where the problem is.
Link Posted: 3/11/2020 8:12:42 PM EDT
[#5]
Thanks for replies, still haven't figured this out yet
Link Posted: 3/11/2020 10:02:31 PM EDT
[#6]
After market bolt handle? If so, is the bolt handle inserted too far?
Link Posted: 3/12/2020 10:53:06 AM EDT
[#7]
Barrel seated all the way? Will it work without the trigger pack in? Have you tried pressing the bolt release?
Link Posted: 3/14/2020 9:03:57 PM EDT
[#8]
Does the bolt head move freely in the bolt carrier? See if the bolt will cycle properly without the bolt handle installed like Steve mentioned. It’ll be a pain to pull back without, but doable.

Any aftermarket parts on the shotgun?

Can you post pictures? I need to see from the bottom with the trigger pack removed and the carrier pulled as far to the rear as if will go.
Link Posted: 3/15/2020 5:29:23 PM EDT
[#9]
Everything is bone stock.
The small divet where the bolt lines up with the barrel extension was binding and grinding against the side of the bolt.

Gunsmith threw blue on everything and verified this was the problem so the curved section of the bolt was polished out and slightly filed.

Thing runs like a top now and no signs of any issues
Link Posted: 3/15/2020 11:26:20 PM EDT
[#10]
I've had this happen several times, it takes a little finesse to get the bolt in/out just right.

The bolt will come out, you'll need to pull on it with a snap.

Hope that makes sense.
Link Posted: 3/16/2020 6:11:48 AM EDT
[#11]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Everything is bone stock.
The small divet where the bolt lines up with the barrel extension was binding and grinding against the side of the bolt.

Gunsmith threw blue on everything and verified this was the problem so the curved section of the bolt was polished out and slightly filed.

Thing runs like a top now and no signs of any issues
View Quote
Was the bolt contacting the ejector spring pin?   Number 85 on this schematic? Inquiring minds are inquiring.
Link Posted: 3/16/2020 5:37:00 PM EDT
[#12]
Be sure the "tail" on the bolt is oriented in the right place. It may be binding inside the tube of the stock or the follower inside that tube is binding.
Link Posted: 3/16/2020 8:36:52 PM EDT
[#13]
Discussion ForumsJump to Quoted PostQuote History
Quoted:

Was the bolt contacting the ejector spring pin?   Number 85 on this schematic? Inquiring minds are inquiring.
View Quote
That looks like the area it was hitting exactly
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