HD extractor springs & CRANE O-rings

[GIFFMANN]

As Marc said, it doesn't hurt to run both. The "kits" I have are the Crane O ring and the Crane HD Spring.

Giff

[M4arc]

As Marc said, it doesn't hurt to run both. The "kits" I have are the Crane O ring and the Crane HD Spring.

Giff

Giff - Tell me more about the Crane HD Spring. How does it compare to the Wolff or Colt HD Spring?

[GIFFMANN]

Giff - Tell me more about the Crane HD Spring. How does it compare to the Wolff or Colt HD Spring?

Good question. I'll look at it closer and let you know....or I'll ask Grant

[Hawkeye]

For some odd reason I thought the black inserts were the ones you didnt want. So you guys are saying blue for rifle and black for carbine correct?

[M4arc]

For some odd reason I thought the black inserts were the ones you didnt want. So you guys are saying blue for rifle and black for carbine correct?

IIRC Troy posted that the color of the insert did not matter and that the only thing it was used for was to denote the upgrade to the HD extractor spring was performed. This info might be wrong or outdated, I don't know but that's what he posted.

[jmart]

I've heard two stories:

(1) Insert color doesn't matter. The only reason there are two different colors was to make it easier for armorers/assembly personnel to differentiate between rifle strength springs and carbine HD springs.

(2) Insert color does matter. The black insert is made of a denser material and should be paired with the HD spring.

Sully subscribes to the latter since, if I remember correctly, he makes that point on his website with his extractor upgrade package. But at the same time, it seems almost counter-intuitive. Part of me thinks the std weight/strength spring would benefit more from additional support than the HD springs since it already runs a stronger spring wire to begin with. Who knows.

In the end, I'm not really concerned too much about the insert color/density, I'm just trying to figure out if I should switch over to the heavier spring along with the addition of the O-ring or does the O-ring by itself offer enough benefit. I guess like someone above said, just consider it added insurance.

[Hawkeye]

So as long as I stick with an HD spring and either a Crane o ring or a Defender, then I'll be on top of things, right....?
I usualy stay up on this kind of stuff, but for some reason I have been lax on this..

[M4arc]

So as long as I stick with an HD spring and either a Crane o ring or a Defender, then I'll be on top of things, right....?
I usualy stay up on this kind of stuff, but for some reason I have been lax on this..

Correct!

Jmart - I certainly doesn't hurt to run an O ring or Defender in addition to an HD spring. No offense to Troy, he's a wealth of information but in this case I would listen to Sully

[twl]

So as long as I stick with an HD spring and either a Crane o ring or a Defender, then I'll be on top of things, right....?
I usualy stay up on this kind of stuff, but for some reason I have been lax on this..

In the case of the D-Fender, it is engineered to provide 4x the normal extractor tension, and does not require any extra power spring. The D-Fender does virtually the entire job by itself anyway, and the spring becomes primarily a device for maintaining the locating position for the D-Fender.

I've been told by Mack, that the black D-Fenders are a bit stiffer than the original blue ones that we used to make, but I have no idea if this also carries over into the colored spring inserts, or if it is just a coincidence that the colors are similar.

I really can't speak to the O-ring situation, because there are so many different ones out there, that there's no way for me to accurately address that. All I can say about the O-rings is that the "O" shape is not ideal for this application(regardless of material used), and our testing showed marked improvements in reliability and longevity when the "D" shape with the wedge profile was introduced.

Several very high round-count tests were done on the D-Fender by Crane, and they never did get it to fail, and issued the DTC Safety Certification for military use. I have a copy of the DTC letter in my posession, and I've posted the text on "another gun website". The key parts of the letter's text were "extensively tested on 3 variations of M16/M4 weapons", "always improved reliability", and "without negative effects".

Yes, it costs alot more than an O-ring.

YMMV.

[Yojimbo]

I've been running both my carbines with obly the Wolff XP extractor spring and they've been running 100%.

Lately I've been thinking of adding a D-Fender as well for some extra Murphy proofing but I was wondering if there can be a negative effect becuase of too much extractor tension.

Does anyone know if too much extractor tension could cause issues with feeding or something else?