Need advise on Lyman GPR trigger group.

Discussion in 'The Gun Builder's Bench' started by Shiloh1944, May 13, 2019.

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  1. May 13, 2019 #1

    Shiloh1944

    Shiloh1944

    Shiloh1944

    32 Cal. MLF Supporter

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    Gentlemen, I have been working on my Lyman GPR flint rifle kit and I have a question. My trigger group does not have a crisp trigger break no matter how I adjust the double set trigger adjustment screw. With the screw all the way in and the back trigger set I still have about 1/8" play before the front trigger will break and I am certain it is more than a 2 or 3 pound pull. I would like to achieve a crisp break with no play at about 2 or 3 pounds. Is there any way I can achieve that with the trigger group that came with the kit or do I need to find another trigger group by a different maker?
     
  2. May 13, 2019 #2

    bubba.50

    bubba.50

    bubba.50

    54 Cal.

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    The adjusting screw between the triggers is intentionally too short in the Italian guns to appease the lawyers. If yer local hardware has metric screws get a longer one and you should be able to adjust them better.

    Another & in my opinion better option would be to drop a set of Davis Deerslayers in it.
     
  3. May 20, 2019 #3

    Gonetocamp

    Gonetocamp

    Gonetocamp

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    I agree with Bubba. 50 regarding the Davis Deerslayer. Also, replace the Lyman Lock Sear Spring with a lighter spring - it isn't necessary if you will always shoot with the set trigger set, however if ever shooting with the front trigger only the lighter spring is much, much better.
     
  4. May 20, 2019 #4

    Phil Coffins

    Phil Coffins

    Phil Coffins

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    I’ve built a few of these and what I do is disassemble the triggers and lightly stone the engaging surfaces. The goal is crisp edges where the trigger engage togather. At this time I replace the adjusting screw with a longer one which for me means drilling and tapping for an English thread which I find easier to get. Oil and reassemble then with the hammer fully down set the trigger and turn the screw in till it trips the front trigger. Then back it out one full turn. Decide then if it’s to light or to heavy to suit you and fine tune.
     
    Griz44Mag likes this.
  5. May 20, 2019 #5

    stewart.leach

    stewart.leach

    stewart.leach

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    The adjustment screw does not adjust weight, it adjusts degree of engagement. These triggers are built to meet a price point- as is the rest of the rifle- and there is some roughness. Consistency can be improved by disassembly and polishing the sides of the trigger bars, especially at the pin holes. Very light stoning of the engagement surfaces will help- place the surface on the stone and pull straight off, do not work side to side, do not change the engagement angles. All you want to do is smooth out high spots.

    Polish the end of the trigger mainspring where it bears on the trigger bar. Try not screwing the spring mount screw down firm- the spring may be putting more pressure on the bar than is needed to release the lock sear. If you do this, secure the screw with a tiny bit of Loctite.

    I have replaced adjustment screws with longer ones from local hardware store, and find the thread fit is much looser than the factory screw. These screws have sometimes loosened up. Found a tiny dab of green (wicking) Loctite a good move.

    In my seldom humble opinion, the Lyman GPR series are as authentic as you are going to get in a factory rifle, are accurate, and a very good value.
     
  6. May 29, 2019 #6

    FishDFly

    FishDFly

    FishDFly

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    "I have replaced adjustment screws with longer ones from local hardware store, and find the thread fit is much looser than the factory screw. These screws have sometimes loosened up. Found a tiny dab of green (wicking) Loctite a good move."

    You can use a pair of Vice grips and "slightly" flatten the threads a bit and screw in the screw.
    If still loose, tighten the grips a small amount and flatten more and screw in again. Repeat until happy.

    Another way is wrap Teflon tape on the treads, that will tighten it up and you can still easily remove it.
     

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