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  1. #1
    Steve M1911A1's Avatar
    Steve M1911A1 is online now Senior Member
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    AMT Backup: Advice and Help Needed

    I just bought an AMT Backup in .45 ACP. It's a DAO, just a little longer than my Semmerling LM-4, and it fits into the same pocket holster and pockets.
    It has the worst stock trigger I've ever experienced! The reach is almost too long, and the pull is well over 15 pounds. It does break nicely for the shot, however.
    I'm going to work on polishing its innards, to see if I can lighten the trigger somewhat.
    Does anybody know whether or not it's OK to shorten or lighten the hammer (main) spring? I worry that it is so involved with retarding the slide's recoil action, that lightening it is not a good idea.
    Any input would be appreciated.

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  3. #2
    Steve M1911A1's Avatar
    Steve M1911A1 is online now Senior Member
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    I took my AMT Backup completely apart, polished everything that moved or rubbed, stoned the hammer-to-trigger-bar contact areas, and polished the finger-contact surface of the trigger to a mirror shine and smoothness.
    Its trigger pull is still off the scale (more than 10 pounds) but it feels subjectively much lighter.
    The one modification that did the most, all by itself, was polishing the trigger surface! Who would'a thunk?

  4. #3
    milquetoast is offline Member
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    I tried that, and got light primer hits/failure to fire, plus failures to feed, presumably because of upsetting the timing of the slide recoil. The mainspring on that gun regulates both recoil velocity (more so than the recoil spring) and trigger pull. Polish yes, cut spring, no. That was my experience, anyway.

    BTW, mine ejects with great accuracy and great velocity into my forehead. I know one is supposed to whittle on the ejector to change the direction of ejection, but does anybody have a formula for exactly where and how much to whittle? Do I take metal off the top of the ejector? The left? The right?

  5. #4
    Steve M1911A1's Avatar
    Steve M1911A1 is online now Senior Member
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    Charlie Petty (master gunsmith) said the very same thing, so I did not cut any springs. All I did was polish the heck out of all the pistol's contact points and surfaces.
    The hammer (main) spring not only helps control slide movement, but also has to overcome one heck of a stiff firing-pin spring.
    Looking at the design really carefully, and speaking as a seat-of-the-pants (i.e., no formal education at it) design engineer, I think that the geometry of the slide-to-hammer contact is more important than mainspring strength. If I ever get unhappy with the effects of my polishing job, I will shorten the mainspring, but I'll have to find a weaker firing-pin spring to go with it. (Of course, that may result in slam-fires...so maybe I won't.)

    Miz' Scarlett, I don't know nuthin' 'bout no ejectors.
    I just close my eyes as I'm pulling the trigger.

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