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Page AR-15 » Troubleshooting
AR Sponsor: bravocompany
Posted: 4/28/2020 10:06:47 AM EDT
Adams Arms EVO upper, Bushmaster Lower, Lancer Magazines

Recently, occasionally the bolt locks back with one round in the magazine.   Happens about 10% of the time, with different Lancer magazines.  The bolt is not catching on the round.  The bolt is being stopped by the bolt catch.

How do I fix it?
Link Posted: 4/28/2020 10:16:53 AM EDT
[#1]
I'd replace the bolt catch spring.  While disassembled, I'd clean the recess the catch sits in and the catch itself.
Link Posted: 4/28/2020 10:17:45 AM EDT
[#2]
Does it do it with every magazine. Put 2 or 3 rounds in the mags you use. See if you can isolate the problem mags. It might be that the follower comes up high enough in that Mag to lift the bolt catch. Or switch followers and try the problem mags again
Link Posted: 4/28/2020 10:27:42 AM EDT
[#3]
I had this issue. 11.5 midlength faxon/maxim cqb brace jp scs combo/M16 carrier. Had to get a heavier buffer.
Link Posted: 4/28/2020 10:51:34 AM EDT
[#4]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I'd replace the bolt catch spring.  While disassembled, I'd clean the recess the catch sits in and the catch itself.
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I had one that the spring plunger was sticking due to debris from anodizing.  Same symptom.
Link Posted: 4/28/2020 11:27:13 AM EDT
[#5]
Discussion ForumsJump to Quoted PostQuote History
Quoted:



I had one that the spring plunger was sticking due to debris from anodizing.  Same symptom.
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View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
I'd replace the bolt catch spring.  While disassembled, I'd clean the recess the catch sits in and the catch itself.



I had one that the spring plunger was sticking due to debris from anodizing.  Same symptom.

I believe it.  Some parts I've used didn't fit quite as smoothly as others.
Link Posted: 4/28/2020 11:35:37 AM EDT
[#6]
Discussion ForumsJump to Quoted PostQuote History
Quoted:



I had one that the spring plunger was sticking due to debris from anodizing.  Same symptom.
View Quote


Did that debris look almost like anti-seize? i assume the stuff in mine was flakes mixed with lube after thousands of rounds looked just like anti-seize lol
Link Posted: 4/28/2020 2:10:58 PM EDT
[#7]
That was it.  Took it apart and the plunger was stuck. Took needle nose pliers to remove it.  Cleaned it up and put it back together.  Works much better.  Will test during next weeks range trip.

Thanks
Discussion ForumsJump to Quoted PostQuote History
Quoted:



I had one that the spring plunger was sticking due to debris from anodizing.  Same symptom.
View Quote

Link Posted: 5/11/2020 1:48:01 PM EDT
[#8]
Range trip successful
Link Posted: 5/11/2020 9:08:59 PM EDT
[#9]
Good to hear!!
Page AR-15 » Troubleshooting
AR Sponsor: bravocompany
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