Help with Malfunction - Bolt not catching first round

[Tactical Yeti]

Hello. If anybody has any ideas on how to solve this malfunction please let me know! I'll try and describe the issue in having as best I can, here it goes:

New BCM lower
New 11.5" BCM upper
New BCM BCG
Vltor buffer tube
Sprinco green spring
H4 buffer

I recently put together this rifle specifically for running suppressed 90% of the time. I took it out to test this afternoon, inserted the magazine and pulled back the charging handle and let go to chamber the first round. Everything sounded good, pulled the trigger and "click". Pulled back the charging handle, looked in and noticed no round had been picked up. I pulled back the charging handle as far as it would go and rode it a bit to see if it would pick a round up and it wouldn't. After multiple attempts the bolt finally caught the middle portion of the brass and the round lodged itself in front of the bolt at an angle. I cleared the round and went to diagnosing the issue but haven't figured it out.

When I insert an empty magazine, the bolt will lock back but when I release the magazine the bolt releases and slams closed.

When trying to pick up that first round the bolt isn't traveling back enough to contact the rear of the bullet.

The magazine I'm using is a pmag and it inserts fully and drops freely.

Any ideas?
Yeti

[KUSA]

Spring too long?

[steyrman13]

Do you have another lower or milspec spring you can try?

[lt211]

Are you using the A5 Vltor buffer tube which is longer than a standard? They do make both.

[steyrman13]

A5h4 buffer with a regular Vltor buffer tube and not the a5 tube could cause the symptoms.

[.46caliber]

I just read Sprinco's page and they're pretty specific about using the green with an A5 tube and A5 buffer.

[Tactical Yeti]

Ugh I think you guys who are saying I have the regular Vltor buffer tube are right. Pulled my stock off and the number goes to 5 where it should be 7, yes?

[steyrman13]

Ugh I think you guys who are saying I have the regular Vltor buffer tube are right. Pulled my stock off and the number goes to 5 where it should be 7, yes?

Yeah I believe that is your problem.

[Tactical Yeti]

When I initially purchased that buffer tube I evidently didn't do enough research. Thought the only difference was one was a 5 stop position and one was a 7 stop - not that they were different lengths.

[Clint]

With a properly setup buffer system, the front face of the bolt should retract approximately 1/4" past the bolt stop when pulled into full recoil position with the charging handle.

Anything significantly different than that is wrong and needs to be corrected.

[Iraqgunz]

Vltor essentially makes two variations of the A5 tube. You need one of the following to correctly use the A5 buffer and spring.

A 6 position tube- https://www.vltor.com/shop/a5-system/re-10a5sr-a5-receiver-extension/

And a 7 position tube- https://www.vltor.com/shop/a5-system/re-a5-a5-receiver-extension/

And you can also get the BCM version- http://www.bravocompanyusa.com/BCM-Intermediate-Receiver-Extension-A5-Buffer-Tub-p/bcm-intermediate-re.htm


When I initially purchased that buffer tube I evidently didn't do enough research. Thought the only difference was one was a 5 stop position and one was a 7 stop - not that they were different lengths.

[lt211]

Vltor RE-A5: A5 Receiver Extension is what you need (seven position receiver extension)

[SteveL]

Vltor RE-A5: A5 Receiver Extension is what you need (seven position receiver extension)

There are more variations of the A5 receiver extension than just the one with 7 stock positions. As Iraqgunz noted above Vltor also makes a 6 position version and BCM offers an 8 position version. Any of them would work for the OP.

[lt211]

youre right, I guess I associate the 6 position RE-10 with the 308 platform and my Vltor kit came with the RE-A5. BCM is an option too...

[ace4059]

Vltor essentially makes two variations of the A5 tube. You need one of the following to correctly use the A5 buffer and spring.

A 6 position tube- https://www.vltor.com/shop/a5-system/re-10a5sr-a5-receiver-extension/

And a 7 position tube- https://www.vltor.com/shop/a5-system/re-a5-a5-receiver-extension/

And you can also get the BCM version- http://www.bravocompanyusa.com/BCM-Intermediate-Receiver-Extension-A5-Buffer-Tub-p/bcm-intermediate-re.htm

Is the only difference between those three a5 buffer tubes is the number of notches? The length of those three are the same, correct? Or am I missing something?

[SteveL]

Is the only difference between those three a5 buffer tubes is the number of notches? The length of those three are the same, correct? Or am I missing something?

You are correct. The length of all 3 is the same. I believe Vltor released the 6 position because people were unhappy that a lot of stocks won't lock into position all the way forward.

ETA: The Vltor tubes are numbered on the top in case your stock has a witness hole so you can look and see which position your stock is in. I don't believe the Bravo tube has this feature.

[titsonritz]

https://www.youtube.com/watch?v=UnrVJT4UU10