What do y'all think of the D-Fender D-ring?

[OD Green]

I installed one even though that I have had no extraction problems and I am running a Colt gold spring with black insert. Anyone else running one?

[Robb Jensen]

They work extremely well, but I use the Crane O-rings. In my experience The Crane O-rings last just as long and cost 1/12th the price.

[snacks]

+1 i think that the defender o rings are overpriced. If one was resourceful. You could find the same set up at a local hardware store for much less. That is what i did and after ten thousand rounds the o ring is still good.

Did i mention that they even come in a pack of ten. :D

[Submariner]

I installed one even though that I have had no extraction problems and I am running a Colt gold spring with black insert. Anyone else running one?

I'm running one and it works. All the rest are Crane O-rings. They work, too.

[M4arc]

I've run them before and I'll run them again. They work great and are designed (hence their shape) for the job. However the crane o-rings work too for a lot less money.

[Kisara]

Ditto the above-
They work, but I get the O-rings for free. For me, that's a no-brainer.

[Heavy Metal]

I like them. I think they are worth the money. 13 dollars is not too much for a part that will last the life of the bolt. MGI will replace it if you have a problem and from what I understand, it will easily last the life of the bolt.

[KevinB]

I run them -- or Crane O rings.

Given our local SODA is out of weapons parts -- I bought more Defenders.

It won't hurt and it will help.
http://img.photobucket.com/albums/v193/EvilKev/Weapons/boltandhat.jpg

http://img.photobucket.com/albums/v193/EvilKev/Weapons/DRing.jpg

[VA_Dinger]

I'm another guy who has run D-Fender's with zero issues. I just don't see the point when CRANE O-rings are a $1 and do the exact same thing.

[Akoni]

What durometer rating and material are the "real" Crane o-rings? Most hardware store o-rings are neoprene and of a low durometer. There is a difference, whether it matters or not, I don't know.

[VA_Dinger]

What durometer rating and material are the "real" Crane o-rings? Most hardware store o-rings are neoprene and of a low durometer. There is a difference, whether it matters or not, I don't know.

I'm not sure, but I've been told the real deal CRANE'S are “different” from a regular o-ring you would get from Home Depot. It must have to do with their temp rating. That being said I’m sure the same o-rings could be found elsewhere.

G&R & Adco advertise theirs are true "CRANE" o-rings and I've never had a problem with either one. Since they are only a $1 I've never seen a reason to try and save a few cents.

[AR-15A3]

I run a D-Fender but only on my Steyr AUG A1 my other ARs use the Crane O-rings from ADCO.

I have no problems before I used them with my AUG and ARs but the extraction feels more positive with them installed.

[sdcromer]

I read somewhere that the Crane o-rings are 70 durometer Viton. These should be available at most hydraulic supply houses.

[Submariner]

http://www.smallparts.com/products/descriptions/orv.cfm

I think it is the one with i.d. 1/8" and o.d. 1/4"

[Akoni]

I'm not sure, but I've been told the real deal CRANE'S are “different” from a regular o-ring you would get from Home Depot. It must have to do with their temp rating. That being said I’m sure the same o-rings could be found elsewhere.


I read somewhere that the Crane o-rings are 70 durometer Viton. These should be available at most hydraulic supply houses.

That would sound about correct to me. Viton o-rings are commonly available but not at home stores/hardware stores.

[twl]

I went into this discussion in depth on the tacked thread about o-rings, so I won't repeat that here.

Mack Gwinn and Jim Sullivan informed Crane about this method of improving extraction with a ring, and also why we continued development into the D ring after first trying the O-ring. They tested our D-Fender and it never failed in their tests, and was issued combat safety certification.

We know what the difference is, and why the difference matters.
My advice is to use whatever you want for the range, but if you are going in harm's way, use the D-Fender. It's more reliable, and there are actual technical reasons why.
You spend more than the price of a D-Fender on a box or two of ammo, and it lasts a long time because it is engineered for the exact application.

You don't pay more for just the ring, you pay for the design experience and testing from the guys like Mack Gwinn and Jim Sullivan, who invented it. To me, that's worth the difference.
Others may think differently.

[KevinB]

twl -- I'm with you on that.
My KAC SR16 upper has been flawless since I added the DFender, with both Mk262 and M855 -- inc some 30 rd mag dumps of Mk262 -- no tbad for a Wylde chmaber SS gun -- I used to notice some FTE's when it got hot with the extractor overiding the rim -- since I went to the DFender - no issues.

Same with my teammates Recce Rifle -- however we did unfortunateky notice his M16A1 lower has autosear hole elongation - and it no longer reliably fires in auto.

[M4arc]

I went into this discussion in depth on the tacked thread about o-rings, so I won't repeat that here.

Mack Gwinn and Jim Sullivan informed Crane about this method of improving extraction with a ring, and also why we continued development into the D ring after first trying the O-ring. They tested our D-Fender and it never failed in their tests, and was issued combat safety certification.

We know what the difference is, and why the difference matters.
My advice is to use whatever you want for the range, but if you are going in harm's way, use the D-Fender. It's more reliable, and there are actual technical reasons why.
You spend more than the price of a D-Fender on a box or two of ammo, and it lasts a long time because it is engineered for the exact application.

You don't pay more for just the ring, you pay for the design experience and testing from the guys like Mack Gwinn and Jim Sullivan, who invented it. To me, that's worth the difference.
Others may think differently.

This is the thread: https://www.m4carbine.net/showthread.php?t=435

There's a lot of great information in there!

[HLDefender]

With good LC ammo -- what is the expected life of a milspec extractor used in semi auto only -- well maintained. As in # of rounds.

Now is there anyone who has the D Ring who has seen an increased round count without FE's over the non D ring setup - ? - same rifle.

Thanks.

HLD...

[dialM4murder]

What size punch do I need to remove the extractor pin on the bolt?

[Robb Jensen]

What size punch do I need to remove the extractor pin on the bolt?

I use the firing pin retaining pin to push out the extractor pin, call me weird. ;)

[Col_Crocs]

+1 i think that the defender o rings are overpriced. If one was resourceful. You could find the same set up at a local hardware store for much less. That is what i did and after ten thousand rounds the o ring is still good.

Did i mention that they even come in a pack of ten. :D

My thoughts exactly. :D

[AirmanAtwood]

What size punch do I need to remove the extractor pin on the bolt?

use your firing pin to push it out. You dont have to push it hard.

[sdcromer]

I always get it started with skinny end of the firing pin.

[dialM4murder]

Sweet, thanks guys.

I too am having extraction issues. I installed a new buffer spring and an H2 buffer. That helped a lot. However, im still getting a FTE about once every 50 rounds. :mad:

My rifle must be really over gassed in that im not short stroking at all with a new buffer spring and an H2 buffer. This is with .223 ammo by the way. I also plan to have the chamber checked as well and have it reamed to a true 556 (if need be). That and the D-ring should do the trick I hope. :)

[QuickStrike]

I have one in my colt. Works good. Probably not that much better than the crane O-rings though.

[seb5]

I ordered 100 from Mcmaster I think. 100 O rings, $5.00 and $6.00 shipping. Now I've got a lifetime supply and put them on my friends and co workers rifles as well.