Extraction issues. Can you identify this BCG?

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Can anybody identify this bolt and carrier? Also, having issues ejecting. Empty doesn't eject and it picks up another round and jams up. Pistol is fairly new and it seemed like it was breaking in and correcting itself, then I cleaned it and the issue is back. Swapping bolts from another rifle and it works fine. Just holding an empty against the bolt and letting go and it flips them right out. Further follow up, I borrowed a spring helper donut from another rifle and that seems to have cleared it up. What's the best course of action, get this one its own donut, or an extra power spring? I have a parts wanted ad in the classifieds.

Back story: I got the BCG in a trade from a co-worker who swears up and down that it's a brand new Anderson that he bought a couple years ago and never used. When I got it, it looked like it had been in a rifle and hand cycled or shot a handful of rounds. It also had the extractor claw broken off. To tell the truth the finish on the carrier looks to good to be Anderson. The only identifying marks are the MPI and two dimples on the bolt and three dimples on the carrier. It's kind of unique in that the front of the carrier has facets machined in instead of a constant round radius. After I received the BCG from him I called around and a local gunsmith had a "good used" extractor he popped on there for $10.

20200927_124835.jpg 20200927_124857.jpg 20200927_124921.jpg 20200927_125004.jpg 20200927_125025.jpg 20200927_125048.jpg 20200927_125114.jpg
 
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When you used the loaner bolt did it have an O ring? If so seems like there is a gas or spring issue somewhere else. If the other carrier did not have an O ring making all things equal then there would appear to be a problem with the bolt or the extractor system that is in it.

Are you running a new extractor spring in it? Do you have the black or blue insert in the spring?
 
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OP
W
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When you used the loaner bolt did it have an O ring? If so seems like there is a gas or spring issue somewhere else. If the other carrier did not have an O ring making all things equal then there would appear to be a problem with the bolt or the extractor system that is in it.

Are you running a new extractor spring in it? Do you have the black or blue insert in the spring?
The loaner bolt had a spring, spring bumper insert, and donut. The bolt in the pictures that I'm having issues with only had spring and bumper insert. I borrowed just the donut and installed it and it cleared up the extraction issues.

The whole BCG was nearly new but had a broken extractor claw. I replaced the extractor but would assume the spring was nearly new / good. It has the black insert.

Where is the spent brass ejecting to? Was it ejecting to 1 o'clock or closer to 5 o'clock?
With a donut installed it seems to eject about 3 o'clock. Without the donut the extractor pulls the empty from the chamber but then let's go before the shell clears the port and is ejected.

Bryan
 

doobee8

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Never assume anything. Replace spring for NEW chrome silicone 5 coil extra power extractor spring and black or blue insert. They say you don't need the donut with the 5 coil spring. Spring co has sets of these. Very cheap insurance. Also what buffer weight and buffer spring are you using?
 
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Since the other bolt had the O ring and your bolt works with the O ring. Seems to me there is another issue. Can you send photos of the extractor? The process of limation would be to run the other bolt without the O ring and if it works fine then the issue would likely be having something to do with the bolt. But since they both run fine with the O ring likely issue is

What size buffer are you running and are you running a stock or extra power buffer spring? Also what kind of a gas block? Set screw, Pinned or clamp?
 
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Never assume anything. Replace spring for NEW chrome silicone 5 coil extra power extractor spring and black or blue insert. They say you don't need the donut with the 5 coil spring. Spring co has sets of these. Very cheap insurance. Also what buffer weight and buffer spring are you using?

I have removed the oring from several of mine, after I updated the spring with BCM springs, which I think are Springco's. functions just fine without the oring.
 
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I have removed the oring from several of mine, after I updated the spring with BCM springs, which I think are Springco's. functions just fine without the oring.
However did they function just fine before the spring upgrades. Are you noticing any difference in function before vs after this unauthorized modification?





i.e. I didn't authorize you to do this to your rifles. :s0112:
 
OP
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So I found a Doublestar parts kit with new extractor, spring, insert, and O ring.

I tried my borrowed BCG without o ring in my carbine and it seemed to function but I didn't run lots of rounds.

Borrowed BCG in my 12.5" mid length pistol, which is the one I'm having issues with, and the borrowed BCG with no o ring isn't reliable.

Intended BCG in my pistol, with the extractor that was installed on it but with new replacement spring and insert but no o ring, not reliable.

Intended BCG in my pistol, with the new extractor from the kit and new spring and insert but no o ring, not reliable.

Intended BCG in my pistol with new extractor, spring, insert, and O ring, seems reliable. Although only 6-7 rnds, ammo in short supply and all.

When I first assembled the gun and started having issues I had an H1 buffer in it and I believe a standard carbine spring. I incorrectly guessed that it was short stroking and swapped in a standard carbine buffer. All testing since has been with the standard buffer and spring. I get the feeling that I should swap in the heavy buffer again. I've been doing some reading and it seems that the shorter the dwell time the more violently the weapon cycles. Along with the need for an O ring. I've seen several suggestions above for springs with no o ring but they're all extra power springs suggested. It's there a reason for extra power spring with no ring over standard power spring with ring?

Bryan

PS, pics of the good used extractor that I had installed on the intended BCG.

20201001_190603.jpg 20201001_190626.jpg
 
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doobee8

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So I found a Doublestar parts kit with new extractor, spring, insert, and O ring.

I tried my borrowed BCG without o ring in my carbine and it seemed to function but I didn't run lots of rounds.

Borrowed BCG in my 12.5" mid length pistol, which is the one I'm having issues with, and the borrowed BCG with no o ring isn't reliable.

Intended BCG in my pistol, with the extractor that was installed on it but with new replacement spring and insert but no o ring, not reliable.

Intended BCG in my pistol, with the new extractor from the kit and new spring and insert but no o ring, not reliable.

Intended BCG in my pistol with new extractor, spring, insert, and O ring, seems reliable. Although only 6-7 rnds, ammo in short supply and all.

When I first assembled the gun and started having issues I had an H1 buffer in it and I believe a standard carbine spring. I incorrectly guessed that it was short stroking and swapped in a standard carbine buffer. All testing since has been with the standard buffer and spring. I get the feeling that I should swap in the heavy buffer again. I've been doing some reading and it seems that the shorter the dwell time the more violently the weapon cycles. Along with the need for an O ring. I've seen several suggestions above for springs with no o ring but they're all extra power springs suggested. It's there a reason for extra power spring with no ring over standard power spring with ring?

Bryan

PS, pics of the good used extractor that I had installed on the intended BCG.

View attachment 757130 View attachment 757131
To answer your question: O-rings can break, melt, or wear away and should not be a required part for your AR15's reliable extraction. The case for the extra power spring is that its a critical part of the extractor, not an add-on. Don't rely on add-ons, it should be able to run reliably with OEM type parts.
 
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