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Thread: Is my bolt spring worn?

  1. #1

    Question Is my bolt spring worn?

    Is my bolt spring worn?

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  2. #2
    Join Date
    Jan 2002
    Location
    Halifax, N.S., Canada
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    That looks like normal compression for a good bolt spring.

    The only way to really know for sure if the spring is bad, is to measure the amount of force it takes to compress it a given difference. Since that if more difficult to do, we just use the simple look and see method. However, the best measure is if the gun is cycling properly. If you are getting bolt stick issues when all other parameters are set properly, then it is most likely a weak bolt spring. This was easy to determine on the level 7 mags, but is not so easy on the level 10 mags. The bolt spring is a consumable item. Every so often (usually around 30000 cycles) , you should just change it as a matter of doing your general maintenance.
    Except for the Automag in front, its usually the man behind the equipment that counts.

  3. #3
    Join Date
    Oct 2001
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    I just had a curious thought. I work with valve spring components. if someone were to get me a measurment of the spring height in gun at rest and bolt forward I can get you a measurment of how much force the spring is actually putting out

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  4. #4
    Join Date
    Jan 2002
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    Halifax, N.S., Canada
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    Quote Originally Posted by BTAutoMag View Post
    I just had a curious thought. I work with valve spring components. if someone were to get me a measurment of the spring height in gun at rest and bolt forward I can get you a measurment of how much force the spring is actually putting out
    If the spring is fully compressed, you won't know how much force it took to do it unless you measure the force. There are measured numbers for bolt springs in some of the threads on AO. I measured the spring for a project a few years ago. I'll have to see if I can find it.

  5. #5
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    the machine I have measures spring for raccing

  6. #6
    Join Date
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    Quote Originally Posted by BTAutoMag View Post
    the machine I have measures spring for raccing
    It probably measures force and the distance.

    Without measuring the force and the distance, can't calculate the spring constant. Once the spring gets used a bit and is weakened, the spring constant will change. Ideally, the spring should last and be the same after 50000 cycles as it is when new. Due to the stress placed on it, that is not the case. The original value will only be valid when new.

    Once you do know the spring constant, you can determine the force exerted by the spring at any given compression distance. The starting force of the spring in a mag can then be calculated by putting the valve into the back of the body until the front of the bolt spring makes contact with the body washer, then measuring the distance the valve is from the back of the body. This distance will be the compression distance when the bolt is at rest in the body, and given the known spring constant, the spring force at that position can be calculated. Knowing the distance that the bolt travels, you can also determine the force exerted by the spring at the far end of the cycle as well.

  7. #7
    Join Date
    Oct 2001
    Location
    Plymouth, WI
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    ... I was just gonna put a spring on it and turn it on.

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