bolt carrier group will not go into battery in upper [upate/results post # 61]

**steelonsteel** · 03-14-14, 12:17

I ordered an upper and a bolt carrier group from a top shelf manufacturer, one who is very well regarded here.

I received them today and the bolt will not fit into the upper. I drop the bolt carrier group into the upper without it being on a lower and it will not go all the way into the barrel extension. It appears that the lugs of the bolt slam into the receiver extension and prevent it from going into battery, either with or without a charging handle. It is then very tough and requires some force to remove it from the upper, like the lugs are sticking on the edge on the extension, but they are not going into the extension at all.

The BCG is assembled correctly.

I have contacted the manufacturer but they have not yet responded [this is just this AM so this is understandable].

What should I look at if I am trying to figure out on my own what is causing this?

Thanks in advance for your time and consideration.

**tehpwnag3** · 03-14-14, 12:28

Check to see if the feed ramps are in the proper location. Then, remove the BCG and cycle the bolt back and forth by hand, is it very tight? It will loosen over time. Next, remove the bolt from the carrier and insert the carrier (minus bolt) into the upper. Check to see if the gas key is binding with the gas tube.

This should start you off. Report back. Let's hope the barrel extension isn't jacked up....

**Onyx Z** · 03-14-14, 12:37

I had the same problem on an upper I built with parts from high quality, well-regarded manufacturers. Turns out the barrel indexing pin came loose and the barrel was spinning ever so slightly in the upper receiver when tightening the barrel nut. I could see the feed ramps slightly out of alignment and the bolt lugs hitting barrel extension lugs. That would be the first thing I would look at, but definitely let the manufacturer make the repairs it if it was a factory built unit.

It's not too common, but it does happen. I sent the barrel in to the manufacturer for inspection and they sent me a new replacement. The whole process took less than a week.

**markm** · 03-14-14, 13:03

Possibly what OnyxZ experienced. Do you have another gun to try the BCG in... and the BCG from that gun in the new upper?

**constructor** · 03-14-14, 13:12

Originally Posted by steelonsteel

I ordered an upper and a bolt carrier group from a top shelf manufacturer, one who is very well regarded here.

I received them today and the bolt will not fit into the upper. I drop the bolt carrier group into the upper without it being on a lower and it will not go all the way into the barrel extension. It appears that the lugs of the bolt slam into the receiver extension and prevent it from going into battery, either with or without a charging handle. It is then very tough and requires some force to remove it from the upper, like the lugs are sticking on the edge on the extension, but they are not going into the extension at all.

The BCG is assembled correctly.

I have contacted the manufacturer but they have not yet responded [this is just this AM so this is understandable].

What should I look at if I am trying to figure out on my own what is causing this?

Thanks in advance for your time and consideration.

Make sure the gas tube is in the center of the track too. If the barrel nut isn't aligned properly it will force the gas tube to one side and bind in the carrier key.

**steelonsteel** · 03-14-14, 13:17

Barrel is not loose, and feedramps are in their proper place. I got a hold of a friends Daniel defense. here's what we tried;

X company carrier alone [no bolt] slides freely.

Daniels complete BCG works.

Daniels bolt in X company carrier works.

X company bolt in Daniels carrier does not work.

Ergo, problem is in the bolt. In further inspection between X company bolt and the Daniels Defense bolt, it appears that the cam pin hole is bored out of time, causing the bolt lugs to strike the engagement lugs of the barrel extension, which keeps it from going into battery.

**markm** · 03-14-14, 13:25

Interesting. Keep us posted. Can you get pics of the good and bad bolt that illustrate this.... without giving up the company?

**Bear1** · 03-14-14, 13:32

Who cares if the company is disclosed? Every manufacturer has an issue from time to time. Plus it might help us as consumers.

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**Onyx Z** · 03-14-14, 13:54

Originally Posted by Angrygrizzly

Who cares if the company is disclosed? Every manufacturer has an issue from time to time. Plus it might help us as consumers.

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He probably wants to keep the manufacturer disclosed until they email him back. That's what I would do (and have done) as the consumer and what I would want if I were the manufacturer. Just giving them a chance to make it good before disclosing.