11.5" - preemptive extractor O-ring or not? - Page 1

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[ARCHIVED THREAD] - 11.5" - preemptive extractor O-ring or not?

Posted: 12/13/2014 2:52:41 PM EDT

My 11.5" is a complete BCM upper with BCG. I'm still trying to get to the range to test and sight it in.

The range costs me money and changing extractor springs ain't no fun to do there without a vise. Install the O-ring or not? I'd be really unhappy if I had FTE issues, I'd be out the $25 range fee.

Posted: 12/13/2014 3:43:27 PM EDT

[#1]

I'd make a go of it without first. Secondly it doesn't take a vise to remove the extractor, comes out really easily with a small punch using just hand pressure. Taking it apart and reassembling it should take less than 5 minutes tops.

Posted: 12/13/2014 3:46:18 PM EDT

[#2]

O rings are really cheap. Size 005 viton if I remember correctly. I use plain rubber 005s and change them often, don't expose them to bore solvent, don't run hundreds of rapid fire rounds, and haven't had any issues.

Posted: 12/13/2014 4:54:29 PM EDT

[#3]

Serious question is their any reason to not run the o rings? (i've never seen any posted)

I've run them in all my ar's for years now and seen no adverse effects nor have i noticed anything bad with the brass (i reload too) .

Posted: 12/13/2014 5:32:44 PM EDT

[#4]

Not.

Posted: 12/13/2014 7:35:41 PM EDT

[#5]

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Quoted:
I'd make a go of it without first. Secondly it doesn't take a vise to remove the extractor, comes out really easily with a small punch using just hand pressure. Taking it apart and reassembling it should take less than 5 minutes tops.

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Yep, easily done with just two humanoid hands.

-OS

Posted: 12/13/2014 7:57:18 PM EDT

[#6]

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Quoted:

Yep, easily done with just two humanoid hands.
and the firing pin tip
-OS

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Quoted:

Quoted:
I'd make a go of it without first. Secondly it doesn't take a vise to remove the extractor, comes out really easily with a small punch using just hand pressure. Taking it apart and reassembling it should take less than 5 minutes tops.

Yep, easily done with just two humanoid hands.
and the firing pin tip
-OS

FIFY

Posted: 12/13/2014 11:25:49 PM EDT

[#7]

Pulling and reinstalling the extractor is something I'd rather not be doing in the booth of an indoor range, which is where I'll be doing this test and sight-in.

Posted: 12/13/2014 11:39:10 PM EDT

[#8]

A new BCM bolt should be good to go

Posted: 12/14/2014 9:09:52 AM EDT

[#9]

Wow! $25 per? I guess Im lucky, my range is $125 for the whole year. Sry that was off subject. Shouldn't a BCM BG have the upgraded springs already from the factory? Just a thought........

Posted: 12/14/2014 9:16:51 AM EDT

[#10]

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Shouldn't a BCM BG have the upgraded springs already from the factory? Just a thought........

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Yes it should, and it being a BCM 11.5" it shouldn't need an O-ring with that added bit of dwell time. To much extractor pressure isn't necessarily a good thing.

Posted: 12/14/2014 12:51:17 PM EDT

[#11]

It's a new BCM BCG with their spring and insert, I was just asking about adding the O-ring. My reasoning is that port pressure is higher on an 11.5" compared to a 14.5", and an O-ring is commonly recommended for 14.5". Screw it, I'll try it with the O-ring and see what happens. Even if I have extraction problems I can still sight it in.

Yeah, it's $25 for centerfire rifles at the local indoor range. My gun club is paid for, but it's an hour drive each way so I only go out there when I can schedule an entire range day.

Posted: 12/19/2014 10:30:30 AM EDT

[#12]

I'm trying to figure out where the O ring goes and can't find it doing a search of the forum. Can someone tell me briefly where it goes? I'm starting a 7.5" pistol build.

Posted: 12/19/2014 10:53:31 AM EDT

[#13]

If you pull the extractor from the bolt you'll see a spring and insert. The O ring goes around that spring and is sandwiched between the extractor and bolt.

Posted: 12/19/2014 10:55:34 AM EDT

[#14]

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Quoted:

It's a new BCM BCG with their spring and insert, I was just asking about adding the O-ring. My reasoning is that port pressure is higher on an 11.5" compared to a 14.5", and an O-ring is commonly recommended for 14.5". Screw it, I'll try it with the O-ring and see what happens. Even if I have extraction problems I can still sight it in.

Yeah, it's $25 for centerfire rifles at the local indoor range. My gun club is paid for, but it's an hour drive each way so I only go out there when I can schedule an entire range day.

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This isn't necessarily true. I'm not sure what size gas ports BCM is using for their 14.5 and 11.5 carbine gas barrels. An 11.5 should have less issues with chamber pressure being too high at the time of extraction because their is a shorter dwell period before the barrel exits the barrel and pressure bleeds off.

As far as the O-ring goes, you have a BCM spring and insert, IIRC their spring is already extra power and the O-ring shouldn't be needed. I wouldn't install it, but I would bring the O-ring in my range bag just in case.

Posted: 12/19/2014 10:56:32 AM EDT

[#15]

Here is where the O-ring goes:

Posted: 12/19/2014 10:56:57 AM EDT

[#16]

Here's a pic I found in the archives from somebody's build thread - he's using a D-Fender instead of an O ring, but same principle:

Posted: 12/19/2014 12:34:41 PM EDT

[#17]

Quote History

Quoted:
Here's a pic I found in the archives from somebody's build thread - he's using a D-Fender instead of an O ring, but same principle:

http://i42.photobucket.com/albums/e346/gun_control/Finished%20AR-15%20Build/DSC01004.jpg

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So thats a "D" ring? does it perform any better?

Posted: 12/19/2014 12:40:32 PM EDT

[#18]

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Quoted:
So thats a "D" ring? does it perform any better?

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Quoted:

Here's a pic I found in the archives from somebody's build thread - he's using a D-Fender instead of an O ring, but same principle:

http://i42.photobucket.com/albums/e346/gun_control/Finished%20AR-15%20Build/DSC01004.jpg

So thats a "D" ring? does it perform any better?

I don't think so. I've never bothered using one though. I bought a 100 pack of viton 0-rings and haven't run out yet. I've got a D-Fender somewhere, came with a bolt I purchased. I never installed it.

Posted: 12/19/2014 10:51:03 PM EDT

[#19]

I've only used BCM's O rings.

Posted: 12/21/2014 5:19:10 AM EDT

[#20]

Why would you not want them? Especially when they are so cheap.

http://www.amazon.com/gp/product/B000MNBMUM/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Life time supply right there for under $5.

Posted: 12/21/2014 9:57:26 AM EDT

[#21]

Quote History

Quoted:

So thats a "D" ring? does it perform any better?

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Quote History

Quoted:

Quoted:
Here's a pic I found in the archives from somebody's build thread - he's using a D-Fender instead of an O ring, but same principle:

http://i42.photobucket.com/albums/e346/gun_control/Finished%20AR-15%20Build/DSC01004.jpg

So thats a "D" ring? does it perform any better?

No it does not and the price is an absolute joke. The boys at Naval Surface Warfare Center Crane Division used round ones and they are still round.

Posted: 12/22/2014 1:02:59 AM EDT

[#22]

Hard to believe a Bravo Co bcg doesn't come with the o ring already installed. When I got my mod 3 grip for my 7.5 I got the spring and o-ring at the same time. Just cheap insurance with the so-called 7.5 problems. A 1/2 hour at Bass pro for a function check cost me $8. A lot closer and cheaper than driving to McMiller.

Posted: 12/22/2014 1:09:38 AM EDT

[#23]

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Hard to believe a Bravo Co bcg doesn't come with the o ring already installed. When I got my mod 3 grip for my 7.5 I got the spring and o-ring at the same time. Just cheap insurance with the so-called 7.5 problems. A 1/2 hour at Bass pro for a function check cost me $8. A lot closer and cheaper than driving to McMiller.

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None of my BCM BCGs have ever had the O ring installed by them - it's always in a separate baggie.

Posted: 12/22/2014 1:59:47 AM EDT

[#24]

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Why would you not want them? Especially when they are so cheap.

http://www.amazon.com/gp/product/B000MNBMUM/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Life time supply right there for under $5.

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Thanks ordered via prime

Posted: 12/22/2014 9:15:45 AM EDT

[#25]

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Thanks ordered via prime

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Quoted:

Quoted:
Why would you not want them? Especially when they are so cheap.

http://www.amazon.com/gp/product/B000MNBMUM/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Life time supply right there for under $5.

Thanks ordered via prime

Damn that is cheap

Posted: 12/22/2014 2:36:38 PM EDT

[#26]

That's a good deal, but the blue ones are better because they are blue.

http://www.ebay.com/itm/BLUE-FDA-VITON-O-RINGS-006-QTY-50-1-8-ID-X-1-4-OD-/190557423834?pt=LH_DefaultDomain_0&hash=item2c5e1b88da

Posted: 12/22/2014 3:26:07 PM EDT

[#27]

My BCM 11.5" works just fine straight from the factory. I do use an H3 buffer, not sure if that matters.

Posted: 12/24/2014 5:10:08 PM EDT

[#28]

Range report - first 150 rounds today with BCM extractor spring, insert and donut plus an H buffer. It ran 100% and is a fun little gun.

Posted: 12/24/2014 6:25:51 PM EDT

[#29]

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Range report - first 150 rounds today with BCM extractor spring, insert and donut plus an H buffer. It ran 100% and is a fun little gun.

http://i892.photobucket.com/albums/ac123/HDF62/11-5_zpsc39579b5.jpg

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Great, now check your brass for extractor bite marks.