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Southpaw_Sonny
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Posted: 9/4/2009 10:21:06 AM
I recently attended a Police Carbine Conference. There was a rundown of aftermarket parts "they" (the speaker) felt should be installed on AR15 Carbine platforms. Everything pretty much made sense in my opinion with one "possible" concern and that being the "D-Fender D-Ring." Has anyone had any experience with this product. I understand what it does it theory, but I am concerned that it may be a part that when fails could cause even more problems. I have never used one before and can't say that I have seen a need, but I do not believe I am an authority by any means. Please add your constructive information regarding this aftermarket part. I am anxious to see what others have learned.
arowneragain
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Posted: 9/4/2009 10:41:00 AM
Originally Posted By Southpaw_Sonny:
I recently attended a Police Carbine Conference. There was a rundown of aftermarket parts "they" (the speaker) felt should be installed on AR15 Carbine platforms. Everything pretty much made sense in my opinion with one "possible" concern and that being the "D-Fender D-Ring." Has anyone had any experience with this product. I understand what it does it theory, but I am concerned that it may be a part that when fails could cause even more problems. I have never used one before and can't say that I have seen a need, but I do not believe I am an authority by any means. Please add your constructive information regarding this aftermarket part. I am anxious to see what others have learned.


By its design (which, BTW, is virtually identical to a $0.03 O-ring) it does greatly increase extractor tension but isn't worked much and is very, very unlikely to fail within the normal service life of other parts (barrel, bolt, extractor). Having said that, if you NEED one, run it for ~3K rounds and change it.

I have O-rings in all my bolts (get a 10-pack at Lowe's) except for a couple which have D-fenders. They all work fine, but, honestly, I wouldn't add one if I didn't see the potential need. IOW, I wouldn't put one on a 20" rifle unless I had extraction problems. As it is, though, all my ARs are either carbine or midlength, so I run an O-ring or D-ring in all of them just to be sure. You WILL notice a difference in extraction force.


While you're at it, go ahead and get a heavy duty extractor spring and a black buffer to go with the D-ring. Be prepared to have a few FTE malfunctions when you first install the kit - plan on running 200 rounds through a carbine to loosen everything up, then you'll be GTG.
...But his word was in mine heart as a burning fire shut up in my bones, and I was weary with forbearing, and I could not stay...All my familiars watched for my halting...But the LORD is with me as a mighty terrible one...

Jeremiah 20 9-11
Indrid-Cold
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Posted: 9/4/2009 11:16:04 AM
[Last Edit: 9/4/2009 11:22:27 AM by Indrid-Cold]
Be sure you get the VITON and not the more common Buna O-rings.

VITON holds up to the heat and solvent exposure.

The Buna will turn to sh*t.

I picked up a bunch from McMaster-Carr for pennies each.

1201T16 (Mil Spec AS568A Dash 006) $4.82/pk of 50
RedFalconBill
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Posted: 9/4/2009 11:49:15 AM
I said this in an earlier thread.

The O-rings will last quite awhile (ie, thousands of rounds). The D-Fender will outlast your barrel.

Whether this difference is important to you, I cannot say.

I use D-Fenders in my carbines and rifles.
alorton
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Posted: 9/4/2009 12:10:23 PM
Originally Posted By RedFalconBill:
I said this in an earlier thread.

The O-rings will last quite awhile (ie, thousands of rounds). The D-Fender will outlast your barrel.

Whether this difference is important to you, I cannot say.

I use D-Fenders in my carbines and rifles.


Me too. All my carbines have them and I recommend them for the rifles I work on at the PD.
Milo5
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Posted: 9/4/2009 12:48:03 PM
Did anyone mention the D-Fender has a lifetime warranty?
If you have any doubts, send it back and they will replace it free.
beavo451
beavo451
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Posted: 9/4/2009 3:43:27 PM
Originally Posted By Milo5:
Did anyone mention the D-Fender has a lifetime warranty?
If you have any doubts, send it back and they will replace it free.


Yeah but for the price of one D-Fender and shipping, you could buy hundreds of O-rings that work just as well.
Milo5
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Posted: 9/4/2009 3:50:09 PM
[Last Edit: 9/4/2009 3:59:23 PM by Milo5]
Originally Posted By beavo451:
Originally Posted By Milo5:
Did anyone mention the D-Fender has a lifetime warranty?
If you have any doubts, send it back and they will replace it free.


Yeah but for the price of one D-Fender and shipping, you could buy hundreds of O-rings that work just as well.


So what?
I have never ever heard of a D-Fender failing by falling apart.
You can send one in and get a new one "Just because."
beavo451
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Posted: 9/4/2009 4:05:20 PM
Originally Posted By Milo5:
Originally Posted By beavo451:
Originally Posted By Milo5:
Did anyone mention the D-Fender has a lifetime warranty?
If you have any doubts, send it back and they will replace it free.


Yeah but for the price of one D-Fender and shipping, you could buy hundreds of O-rings that work just as well.


So what?
I have never ever heard of a D-Fender failing by falling apart.
You can send one in and get a new one "Just because."


Okay so why would spend $15 + on something that should last a life time when you can spend $3 for a few o-rings that would last you just as long? And you can buy several more o-rings for the cost of that stamp to mail your D-Fender in to get your "free" replacement.
stevenb
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Posted: 9/4/2009 4:12:15 PM
My old Defender melted in the Hoppes.
W_E_G
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Posted: 9/4/2009 4:23:01 PM
Note to self: Do not soak D-Fender in Hoppes.
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They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety. - Benjamin Franklin, 1775
HeavyMetal
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Posted: 9/4/2009 4:25:06 PM
[Last Edit: 9/4/2009 4:26:05 PM by HeavyMetal]
Originally Posted By stevenb:
My old Defender melted in the Hoppes.


You sure it wasn't a knock-off? There is a knock off floating around and they tend to fail easily. Call Mack Guinn at MGI if you really think it was a D-Fender. I'll be you could soak a real one in a jar of Hoppes and have no issues.


The D-Fender will also not make your extractor movement so stiff it causes problems. It does leave a tad of room for a bit of flex.
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stevenb
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Posted: 9/4/2009 4:57:46 PM
Yes, it was real. It came with the MGI buffer I bought from Brownells.

I didn't soak it long either. Several weeks later, I noticed some dark greenish goo on the bolt. I kept wiping it down but it kept coming back. So I took the extractor out and the Defender was gone and the channel was filled with the goo. I'd send it back, but I'd have to send patches back.

The trouble with soaking it without removing the extractor claw. So there was probably Hoppes still present for a long period of time.

Careful with that Hoppes and anything rubber/plastic.
Redbone
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Posted: 9/4/2009 5:16:40 PM
You could also just buy the BCM bolt reliability kit which has better extactor spring, black insert and O ring.
F1fanatic
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Posted: 9/4/2009 5:23:44 PM
A buddy of mine and I were comparing his M&P15 to my RRA Entry Tactical. His had the D-ring and mine did not. I noticed his extractor had a recess for the ring to ride in. Can I add one on my RRA even though the recess is not present on the extractor?

Also what are the sizes of these O-rings for the defender?
Grimjaw5
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Posted: 9/4/2009 6:27:14 PM
Originally Posted By Indrid-Cold:
Be sure you get the VITON and not the more common Buna O-rings.

VITON holds up to the heat and solvent exposure.

The Buna will turn to sh*t.

I picked up a bunch from McMaster-Carr for pennies each.

1201T16 (Mil Spec AS568A Dash 006) $4.82/pk of 50


Or
Viton Rubber Orings # 006 50 pcs 1/8x 1/4x 1/16
$3.45 for 50 shipped
DOE
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Posted: 9/4/2009 9:06:10 PM
The Dfender/Oring was part of Colt's original M4A1 reliability upgrade package. All of our SWAT guns have them. A 400% increase in extraction. They work well with shorties.
rooster144
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Posted: 9/4/2009 9:17:38 PM
Originally Posted By beavo451:
Originally Posted By Milo5:
Originally Posted By beavo451:
Originally Posted By Milo5:
Did anyone mention the D-Fender has a lifetime warranty?
If you have any doubts, send it back and they will replace it free.


Yeah but for the price of one D-Fender and shipping, you could buy hundreds of O-rings that work just as well.


So what?
I have never ever heard of a D-Fender failing by falling apart.
You can send one in and get a new one "Just because."


Okay so why would spend $15 + on something that should last a life time when you can spend $3 for a few o-rings that would last you just as long? And you can buy several more o-rings for the cost of that stamp to mail your D-Fender in to get your "free" replacement.



I think the reasoning behind it is that the D-Fender wouldn't crap out at a critical moment, where an o-ring might hit that "X" amount of rounds and fail at precisely the time you don't need it to.

I don't use a D-Fender, and I would imagine the problem above could be solved by simply replacing your o-ring at the appropriate times. I was just chiming in on what the logic behind having one might be, aside from any enhanced performance in extraction.
Milo5
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Posted: 9/4/2009 10:26:54 PM
Originally Posted By stevenb:
Yes, it was real. It came with the MGI buffer I bought from Brownells.

I didn't soak it long either. Several weeks later, I noticed some dark greenish goo on the bolt. I kept wiping it down but it kept coming back. So I took the extractor out and the Defender was gone and the channel was filled with the goo. I'd send it back, but I'd have to send patches back.

The trouble with soaking it without removing the extractor claw. So there was probably Hoppes still present for a long period of time.

Careful with that Hoppes and anything rubber/plastic.


I just dropped one in a small bottle of Hoppes to see what happens.
You don't even need to go to D-Fender if their part melted, Brownells will replace it.
Send a copy of your receipt/shipping order with the MGI Buffer item circled back to Brownells with a letter explaining what happened, they will ship you a new D Ring postage paid.
cray6031
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Posted: 9/4/2009 11:27:29 PM
What makes the dring different from bravos's upgrade kit?
"To disarm the people (is) the best and most effectual way to enslave them."- George Mason
Milo5
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Posted: 9/4/2009 11:53:20 PM
Originally Posted By cray6031:
What makes the dring different from bravos's upgrade kit?


Well, for one, The D Ring isn't supposed to melt in Hoppes solvent or any other cleaner or lubricant for that matter.
The elasticity of the material is designed to last the life cycle of an average bolt or about 30,000 rounds, sounds like a lot of ammunition but it really isn't.
The material can stand up to heat in excess of 600 degrees Farenheight and cold to -30 F.

Like I said, I haven't seen one fail or melt so I am going to do a little test.

I have no idea what material the Bravo Co. O ring is made of having not seen or used one.
cray6031
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Posted: 9/5/2009 12:21:36 AM
I'm not sure either but it looks like just an o ring. I'm sure you can contact Bravo on the industry page and they will send you one to do your tests on.
"To disarm the people (is) the best and most effectual way to enslave them."- George Mason
DOE
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Posted: 9/5/2009 2:39:33 PM
Can't speak for the material composition, but the the Dfender is shaped like a "D", which matches the shape of the extractor recess in the bolt.
RedFalconBill
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Posted: 9/5/2009 4:52:18 PM
Originally Posted By Milo5:
I just dropped one in a small bottle of Hoppes to see what happens.


Has it melted yet?
alorton
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Posted: 9/7/2009 10:26:33 AM
Originally Posted By RedFalconBill:
Originally Posted By Milo5:
I just dropped one in a small bottle of Hoppes to see what happens.


Has it melted yet?


It has been a couple days, any word on the Hoppes test yet?
Milo5
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Posted: 9/7/2009 11:28:08 AM
Originally Posted By alorton:
Originally Posted By RedFalconBill:
Originally Posted By Milo5:
I just dropped one in a small bottle of Hoppes to see what happens.


Has it melted yet?


It has been a couple days, any word on the Hoppes test yet?


Nope.
I'm going to leave it in there a while longer.
I have a start of test pic and will take an end of test pic and post them.
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