Page 17 of 21 FirstFirst ... 71516171819 ... LastLast
Results 161 to 170 of 203

Thread: HD extractor springs & CRANE O-rings

  1. #161
    Dano5326 Guest
    if your stick works.. it works. Most times silly add ons not needed. Seldom with rifle or middy.

    In initial SOCOM use "crane" o'ring often used on regular m16 bolts & extractor springs (not m4a1), more easily ordered through the mil system, on 10.3/10.5" CQBR uppers & 14.5" often with suppressors. A nice quick fix for extraction problems on an nearly over-gassed fast reciprocating shorty. These guns often also had early gas port erosion from rough firing schedules and use of frangible ammo.

    If you want 200 at a time.. you can get the correct O'rings from LMT

  2. #162
    Join Date
    Jul 2006
    Posts
    2,705
    Feedback Score
    0
    Correct o-rings:

    http://www.mcmaster.com

    1201T16

  3. #163
    Join Date
    Jul 2006
    Location
    Oregon
    Posts
    3,459
    Feedback Score
    2 (100%)
    While the o-ring may not be "needed" on mid or rifle guns they are used on the Mk12.

    We use the rifle spring and o-ring on all our rifles from 7.5" up to 20", 5.56 and 6.8 without any issues.
    I have done some full auto testing in a 10.5" with an old SP1 extractor spring with the white buffer and an o-ring, ran like a champ. I don't worry about the an extra power extractor spring or buffer color with an o-ring.

  4. #164
    Join Date
    Jul 2006
    Posts
    2,705
    Feedback Score
    0
    Agreed. Blue/black insert are both fine.

    And this cannot be over-stated. It is not that you don't "need" an extra-power spring if you have an o-ring, but extra-power springs are actually bad because they are more likely to break. So the way to think about it is that the o-ring saves you from having to resort to a high-stressed spring.

    Once you have the o-ring to add tension, the goal should be to use the lowest-stressed spring, which should give the longest life.

  5. #165
    Join Date
    Apr 2009
    Location
    FL -Where it's summer 10.5 months out of the year
    Posts
    4,114
    Feedback Score
    17 (100%)
    Quote Originally Posted by rsilvers View Post
    It is not that you don't "need" an extra-power spring if you have an o-ring, but extra-power springs are actually bad because they are more likely to break. So the way to think about it is that the o-ring saves you from having to resort to a high-stressed spring.
    Without starting an argument, how did you come to this conclusion? How I understood it, just because a spring is stronger, doesn't mean it is under more stress. I could be wrong. But I know that Colt's new gold colored extractor spring is 'extra power' compared to what it's replacing..... and that the .mil has tested it to many thousands of rounds more than the weaker spring it replaced. I'm not an engineer.....im just trying to wrap my head around the issue.

  6. #166
    Join Date
    Jul 2006
    Posts
    2,705
    Feedback Score
    0
    Just measure up the spring and put it into spring design software.

    The new Colt spring seems to double the force without having that much more stress. So if I wanted to use an extra-power spring, I would pick the Colt design. I would never use it with an o-ring.

    The HK 416 spring is not extra-power and seems identical to the old Colt spring.

    By the way, I put the USGI rifle-length action spring into spring design software and it claimed it would last for a million cycles. Not sure if that is correct or not. The important thing from that is the action spring is not under-designed and so there is no reason to look for ways to improve it. 17-7 is the best material for it due to corrosion resistance. You could do A228 music wire or certified (not commercial) chrome-silicon if you painted the spring. The software thought either would make it last 10 million cycles.

    By the way, a sure-fire way to know if your action spring is out of spec is to remove your upper and put the lower on a scale. Balance it so it stands by itself. Zero the scale. Push on the center of the buffer buffer until it just starts to move. Replace the spring if you have less than 5.3 lbs of force on the scale. 5.8 is normal. More than 6.3 is out of spec.
    Last edited by rsilvers; 08-11-10 at 08:41.

  7. #167
    Dano5326 Guest
    haha ah HA ha.. holy bat dung! Bathroom scale AR metrics, that is a new level of AR-nerdery, nice!

    What has worked for me on Operationall standard gas system M4/shorty & I'm not paying for the parts, new:
    -bolt 5K (see failures on rough firing schedules at 8-14k)
    -action spring 5k
    -barrel 10-15K, or gas port elongates &/or cyclic changes, &/or when won't group at 2-300


    I'm sure some bean counter would have a chart of inefficiency for this replacement matrix, however I can't remember when I had an issue that wasn't magazine related.

    Life cycle cost using legacy... Bolt $35, action spring $2, barrel, $175... I would suspect cheaper and less backside pain than buying HK416 or whatever new phaser & dealing with their O&M BS.

    BTW the HK416 action springs I have had my claws on (replacement uppers) are definitely stiffer than the standard ones that were in the legacy lowers.
    Last edited by Dano5326; 08-11-10 at 15:45.

  8. #168
    Join Date
    Jul 2006
    Posts
    2,705
    Feedback Score
    0
    I use a digital postal scale.

    Yes, the 416 action spring has fewer coils than the M4 spring. It is stiffer. I just did the scale test on a 416 and got 8.0 lbs (for when the buffer just starts to move - if you move it an 1/8 of an inch it might read 8.2 or 8.4 lbs).

    And maybe that type of spring offers some advantage. I would consider that.

    The buffer is the same weight as an H2 buffer (within a few grams - both are 130-132 or so grams or around 4.6 - 4.7 oz).

  9. #169
    Join Date
    Sep 2008
    Location
    KY
    Posts
    625
    Feedback Score
    38 (100%)
    I am lost, I thought this thread is about extractor spring and inserts? How are we now comparing buffer springs.
    -They who would give up an essential liberty for temporary security, deserve neither liberty or security- Benjamin Franklin

    -Whoever appeals to the law against his fellow man is either a fool or a coward. Whoever cannot take care of himself without that law is both. For a wounded man shall say to his assailant, "If I Live, I will kill you. If I Die, You are forgiven." Such is the Rule of Honor.- Lamb of God- Omerta

    ابن بيت وأنا كافر

  10. #170
    Join Date
    Oct 2006
    Posts
    257
    Feedback Score
    5 (100%)
    So,

    -Colt spring AND O-ring/D-Fender

    -or-

    -Colt spring AND nothing?

Page 17 of 21 FirstFirst ... 71516171819 ... LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •