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Thread: Help with A5 buffer choice

  1. #31
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    Quote Originally Posted by hk_shootr View Post
    Drill a hole about 3/16” deep in a tungsten weight.
    Drilling tungsten isn't as easy as you think.

  2. #32
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    Quote Originally Posted by MistWolf View Post
    But, if the stiffer spring delays opening, wouldn't that slow down the cyclic rate?
    It does, but the overall effect seems to be an increase in cyclic rate. The additional force at maximum compression means greater acceleration of the reciprocating mass. See this comparisons of carbine springs with a Sprinco blue (the principle is the same):

    http://www.vuurwapenblog.com/reviews...e-differences/

    It's important to use a quality milspec spring, since cheaper ones may lead to erratic cyclic rates.



    Sent from my ZTE A2017U using Tapatalk

  3. #33
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    That was a Sprinco blue spring. It is shorter than the green and there's nothing to indicate the compression and relaxation rate are the same.
    INSIDE PLAN OF BOX
    1. ROAD-RUNNER LIFTS GLASS OF WATER- PULLING UP MATCH
    2. MATCH SCRATCHES ON MATCH-BOX
    3. MATCH LIGHTS FUSE TO TNT
    4. BOOM!
    5. HA-HA!!

    -WILE E. COYOTE, AUTHOR OF "EVERYTHING I NEEDED TO KNOW IN LIFE, I LEARNED FROM GOLDBERG & MURPHY"

    http://i115.photobucket.com/albums/n289/SgtSongDog/AR%20Carbine/DSC_0114.jpg
    I am American

  4. #34
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    Quote Originally Posted by MistWolf View Post
    But, if the stiffer spring delays opening, wouldn't that slow down the cyclic rate?
    Not really. Whatever it does to delay the initial movement of the bolt will be countered by increasing the bolt velocity going into battery.

    Springs are incredibly efficient, and will give you back almost all the energy you put into them. Most self loading guns rely on the impact of the bolt/slide to the rear to dissipate some of bolt energy as heat (compression of the elastomer tip of the AR buffer when it impacts), and then the spring returns the bolt to battery. When you use a stronger spring than designed, you've stored some of that impact energy instead of letting it go into the frame, and then you put it back into the forward movement of the bolt. The stronger spring essentially causes the bolt to "short stroke" instead of bottoming out with the full designed force.

    Whatever kind of self loading mechanism you have, the best way of moderating the energy fed into the bolt/slide is by adding mass - like how a .40 USP has a heavier slide than a 9mm USP. In the case of a gas powered rifle, you also can control the energy directly by limiting the gas. Springs in either case just shift the energy around - it doesn't go away.

    If I couldn't affect the gas or bolt/buffer mass, I would want to use a softer/thicker elastomer to dissipate more energy at the rear of bolt travel and a standard spring to keep forward velocities in check.

    The other thing you can do with hammer fired weapons is to use a different leverage relationship between the hammer and bolt, since that only affects the first bit of bolt movement and not the rest of the cycle. Stiffer mainsprings or a squared firing pin stop in 1911s accomplishes this.

  5. #35
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    Quote Originally Posted by GH41 View Post
    Drilling tungsten isn't as easy as you think.

    Interesting, I drilled a tungsten weight just last week.....cutting fluid, patience and a cobalt bit.
    Easy peasy.
    Last edited by hk_shootr; 12-13-18 at 20:18.
    Proper Planing Prevents Piss Poor Performance.......

  6. #36
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    Quote Originally Posted by Gödel View Post
    Not really. Whatever it does to delay the initial movement of the bolt will be countered by increasing the bolt velocity going into battery.

    Springs are incredibly efficient, and will give you back almost all the energy you put into them. Most self loading guns rely on the impact of the bolt/slide to the rear to dissipate some of bolt energy as heat (compression of the elastomer tip of the AR buffer when it impacts), and then the spring returns the bolt to battery. When you use a stronger spring than designed, you've stored some of that impact energy instead of letting it go into the frame, and then you put it back into the forward movement of the bolt. The stronger spring essentially causes the bolt to "short stroke" instead of bottoming out with the full designed force.

    Whatever kind of self loading mechanism you have, the best way of moderating the energy fed into the bolt/slide is by adding mass - like how a .40 USP has a heavier slide than a 9mm USP. In the case of a gas powered rifle, you also can control the energy directly by limiting the gas. Springs in either case just shift the energy around - it doesn't go away.

    If I couldn't affect the gas or bolt/buffer mass, I would want to use a softer/thicker elastomer to dissipate more energy at the rear of bolt travel and a standard spring to keep forward velocities in check.

    The other thing you can do with hammer fired weapons is to use a different leverage relationship between the hammer and bolt, since that only affects the first bit of bolt movement and not the rest of the cycle. Stiffer mainsprings or a squared firing pin stop in 1911s accomplishes this.
    My point was, if you delay the opening and speed up the closing, it's a wash
    INSIDE PLAN OF BOX
    1. ROAD-RUNNER LIFTS GLASS OF WATER- PULLING UP MATCH
    2. MATCH SCRATCHES ON MATCH-BOX
    3. MATCH LIGHTS FUSE TO TNT
    4. BOOM!
    5. HA-HA!!

    -WILE E. COYOTE, AUTHOR OF "EVERYTHING I NEEDED TO KNOW IN LIFE, I LEARNED FROM GOLDBERG & MURPHY"

    http://i115.photobucket.com/albums/n289/SgtSongDog/AR%20Carbine/DSC_0114.jpg
    I am American

  7. #37
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    Quote Originally Posted by MistWolf View Post
    My point was, if you delay the opening and speed up the closing, it's a wash
    It's a wash if your only concern opening speed and not feed jams.

    However, a spring in its most extended position (bolt in battery) is going to have the least ability to affect bolt opening speed compared to a weaker spring. The biggest effect will be at full compression, not where you want it.

  8. #38
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    Quote Originally Posted by Gödel View Post
    It's a wash if your only concern opening speed and not feed jams.

    However, a spring in its most extended position (bolt in battery) is going to have the least ability to affect bolt opening speed compared to a weaker spring. The biggest effect will be at full compression, not where you want it.
    Do you know how fast a carrier has to run before it will outrun a modern AR mag? Pretty damn fast! I had a grossly over-gassed shorty with stupid high carrier speeds. It never outran any of my magpul mags or modern GI mags. It never had a feed jam, even when I used it with a full auto lower.

    In any case, when used with an A5 RE, the green spring gives my ARs smoother operation than a standard rifle spring does.

    If you go back, you'll see I was questioning the claim that a stronger springs delays opening, speeds closing while giving higher carrier speeds. Seems to me there is a contradiction in there, someplace
    Last edited by MistWolf; 12-14-18 at 00:18.
    INSIDE PLAN OF BOX
    1. ROAD-RUNNER LIFTS GLASS OF WATER- PULLING UP MATCH
    2. MATCH SCRATCHES ON MATCH-BOX
    3. MATCH LIGHTS FUSE TO TNT
    4. BOOM!
    5. HA-HA!!

    -WILE E. COYOTE, AUTHOR OF "EVERYTHING I NEEDED TO KNOW IN LIFE, I LEARNED FROM GOLDBERG & MURPHY"

    http://i115.photobucket.com/albums/n289/SgtSongDog/AR%20Carbine/DSC_0114.jpg
    I am American

  9. #39
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    Quote Originally Posted by MistWolf View Post
    Do you know how fast a carrier has to run before it will outrun a modern AR mag? Pretty damn fast! I had a grossly over-gassed shorty with stupid high carrier speeds. It never outran any of my magpul mags or modern GI mags. It never had a feed jam, even when I used it with a full auto lower.

    In any case, when used with an A5 RE, the green spring gives my ARs smoother operation than a standard rifle spring does.

    If you go back, you'll see I was questioning the claim that a stronger springs delays opening, speeds closing while giving higher carrier speeds. Seems to me there is a contradiction in there, someplace
    Unless you combine overgassing with a stronger spring, there is no reason the bolt closing speeds are going to be anywhere as high as the opening. The opening velocity is absorbed by the impact of the buffer on the back of the buffer tube. So there isn't a good reason for a standard spring to close the action much faster than a correctly gassed action.


    Imagine a spring that is twice as strong as required. It will resist BCG movement twice as hard and will cause it to rapidly short stroke, opening and closing at the same rate because it never dumps any energy into the buffer tube.

  10. #40
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    Quote Originally Posted by MistWolf View Post
    If you go back, you'll see I was questioning the claim that a stronger springs delays opening, speeds closing while giving higher carrier speeds. Seems to me there is a contradiction in there, someplace
    I'm not the only one who thinks this is the case. Read this thread:
    https://www.m4carbine.net/showthread...se-cyclic-rate

    Quote Originally Posted by lysander View Post
    The stiffer the spring the higher the cyclic rate.

    The force returning the bolt to the forward position is stronger, so the acceleration is higher.

    How fast the bolt slows down on the backward trip is largely unchanged due to the extreme force used to accelerate it.

    The piston force is on the order of 1500 to 2000 pounds, so 2 or 3 lb/ins increase in spring rate is not going to change the time taken to get the carrier to the back of the extension by any appreciable amount, but, once the buffer bottoms out in the rear of the extension the velocity is zero, so all forward acceleration comes from the spring. Stiffer spring more force; more force, higher acceleration; higher acceleration, less time....
    Last edited by bruin; 12-14-18 at 02:59. Reason: tapatalk

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