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Thread: Bolt over base in new LMT MRP

  1. #21
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    Against my better judgement, I will respond one more time.

    The empty fails eject when the extractor fails to hold the extracted case against bolt face. If the case is not held against the bolt face, the ejector spring isn't compressed. If the ejector spring is not compressed, the ejector cannot eject the case. Call it what you want, but the root cause is still a failure of the extractor. Therefore, I call it a failure to extract. A loose case in the action blocks the feeding of the next round from the magazine. When that happens, the bolt pushes the round partially from the magazine. However, the loose case stops the round from feeding completely and the bolt pushed forward and up and over the rim (base) of the fresh case. Bolt over base. Sometimes, after causing the bolt over base, the empty is pushed out of the ejection port. This leaves only the bolt over base. It's no more complicated than that.

    My research is based on hands on application of decades of professional troubleshooting experience and techniques. I don't care what the internet says. I do not trust what the internet says. I don't care if you think I'm full of it. I care about getting machines working right in the real world. I know what my successes and more importantly, what my failures were and how I worked through them.
    Quote Originally Posted by sinister View Post
    There are two kinds of nations in the world -- those that use Metric and those who have walked on the moon.
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  2. #22
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    Quote Originally Posted by sig1473 View Post
    I didn't want to chime in but there is some wrong info right here. The 2x LMT extractor springs are not similar to the take down/pivot springs. They do not have the same rigidity. I would advise against making your own out of these. They appear closer/if not exact to regular ejector/safety select springs. I took a pic of the springs in question. I'll let you be the judge.

    Top: Ejector/Safety select spring
    Middle: LMT enhanced extractor springs
    Bottom: Take down/pivot spring
    Attachment 54138
    I see what you're saying. Looks like I got it mixed up as to which spring I used. Thanks for the photo and the correction.
    Quote Originally Posted by sinister View Post
    There are two kinds of nations in the world -- those that use Metric and those who have walked on the moon.
    http://i115.photobucket.com/albums/n289/SgtSongDog/AR%20Carbine/DSC_0114.jpg
    I am American

  3. #23
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    Quote Originally Posted by Rifleman_04 View Post
    The first malfunction you described is a failure to eject so you still don’t know what a bolt over base malfunction is or what you are talking about. You are spreading mis information on an open forum that used to be known for good info. Go do some research.
    Mistwolf and Rifleman 04, Everyone appreciates your input on the forum. Having said that at times I think we misinterpret things we read or what others say. Sometimes we make mistakes, so in my opinion let's keep it easy with each other.

    Anyhow, A fail to eject is just that, a fail to eject. It can be an extractor root cause, but it's not a fail to extract. The unlocking, extracting and ejection portion in the cycle of operation can be complicated in a sense and have many underlying causes. They are also simple as the gun tells you a story and you can more easily pinpoint the problem if you follow the cycle of operation. Remember, if the casing came out of the chamber-it was extracted.

    Hope that helps out on this fine Sunday morning, so if your glass is half full and you are bitching-pour it in a small one and be happy
    GET IN YOUR BUBBLE!

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