Sear/post angles?

Discussion in 'Maintenance / Tweaks / Technical Difficulties / So' started by lycanthrope, Aug 24, 2006.

  1. lycanthrope

    lycanthrope Guest

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    OK. Not being one to leave well enough alone, I've been looking hard at my M40's trigger design....I've been tweaking springs a bit, but also looking at the mating surfaces between the sear and where it is falling off the post. Has anyone taken an India stone to this? Not changing any angles, just smoothing and evening the surfaces.

    BTW, anyone know how much a new sear and post costs? I'd be willing to do some serious experimentation and post the results.
     
  2. bigtaco

    bigtaco Active Member

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    i've only used 1000 grit on a mirror. worked well enough for me.

    to me the real key for polishing in that area is where the sear falls off the post.

    love to hear about any experimenting.
     

  3. MrApathy

    MrApathy Active Member

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    I am nervous about taking any stone to the sear. most I have done is wire wheel brush and polishing bit.

    been meaning to ask BT about a possible mod to get a competition trigger

    maybe new spring set for sear and or striker.

    dont have much time to devote to such stuff as I am going back to school.
     
  4. bigtaco

    bigtaco Active Member

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    been thinking about making a new trigger bar that would get you around 2 pounds!!! also, thinking about a new sear that gives you even shorter trigger reset on follow up shots.

    don't have time to tinker because i'm in the slow process of starting a business.

    but right now i'm in summer-remodel-before-the-cold mode.

    anyone want a two pound trigger? not for carry, just for competition.


    or is 2 too light? ever try to shoot an ar with a 1 pound trigger? almost too light.

    maybe 3. we'll see.
     
  5. lycanthrope

    lycanthrope Guest

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    a 2-3# trigger would be perfect on these guns. I've loaded up some 200gr .40 caliber bullets to minor power factor and the recoil is flatter than my STI Edge with tungsten cone and guiderod. Ridiculously fun to shoot. Now, if they only made a 5"!!!!

    Are you working a better geometry with the trigger bar? How about a titanium bar so you could tweak the springs for the lightest reset?

    I'm pretty sure the sear could be shortened up and reduce creep without risk of doubling. I haven't decided if the pull just wouldn't be better with a reduced power firing pin spring and drilling holes in the sides of the rear of the firing pin to reduce weight and increase the speed (would also likely eliminate the firing pin hanging up when overlubed). My FP spring already lights CCI small rifle primers 100% so this would have to be noticeable.
     
  6. Fredhead

    Fredhead New Member

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    I bought the brownell's spring kit for the extractor
    add-on. Since I had 143 1/2 inches of springs left,
    one day I cut one down and tried it in the striker.
    The original I keep in a pill bottle in my range bag.
    Never put it back in the gun. I can only estimate, but
    I'd guess the pull is 30% to 50% lighter. I have been
    able to compare it with a stock S9, it's much lighter.
    Maybe 1500 rds since, including plenty Win. Never
    had any malf.
     
  7. lycanthrope

    lycanthrope Guest

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    And.....how much pressure is on the sear of the M series guns? The sear contact surface is huge. I'd love to mill out the center and have hooks like on a 1911 hammer. Reduce friction there by 1/3.

    Send me sears. I'm ready to Dremel. :wink:
     
  8. MrApathy

    MrApathy Active Member

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    the most pressure is probably from the gun firing and slide cycling with firing pin smacking the front of the sear then the rear to reset it.

    easiest way is with springs

    another way may be to make a sear like the M&P has. sear wouldnt move in the subframe just pivot releasing the striker. bit scary
     
  9. lycanthrope

    lycanthrope Guest

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    That's not really that bad. The sear contact area on the post is at least 5x that of a comparable 1911....and that's conservative. As long as the sear doesn't bounce off the post, things should be OK. Having two hooks would minimize breakage. The trick is keeping them even and rounding the corners to avoid stress fractures.
     
  10. theFiasco

    theFiasco Guest

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    Fredhead,

    You replaced spring #46 in the parts drawing with a Brownell's spring?

    Thanks for the info,

    -tF
     
  11. Fredhead

    Fredhead New Member

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