trigger spring weight affects the force of primer strikes?

Discussion in 'Modern Firearms' started by corndogggy, Feb 11, 2013.

  1. corndogggy

    corndogggy 12 pointer

    Jul 20, 2005
    Apparently I'm confused on the role played by hammer vs. trigger springs. I thought like on an AR they could be totally independent, meaning you could have any trigger weight you wanted while retaining the same hammer spring weight. JP says it don't work that way though. If you want their 3 pound competition trigger, you have to always use real good handloads because cheap factory loads won't work well. If you want to have good primer strikes with crappier ammo but still have a fairly light trigger, get their 3.5 pound enhanced reliability trigger. If you need 100% reliability on the primer strikes, get a 4 or 4.5# duty trigger. Basically a lighter trigger also means lighter primer strikes.

    A Geissele SSA-E is apparently the same way. It's 3.5 pounds and comes with a lighter hammer. They just act like it's faster though, don't warn about light primer strikes.

    Anyway, can you not get a light trigger along with a hammer that strikes the primer as hard as a heavy trigger? I'm guessing that accidental discharges may be an issue with a heavy hammer but light trigger but I don't know exactly.
  2. GunCat

    GunCat 8 pointer

    Jan 26, 2006
    Fairview, KY
    The trigger spring in this case (AR) is basically just there to reset the trigger after it has been pulled. It has very little to add to the trigger pull weight (unless you go to a really heavy trigger spring). However, In addition to causing a harder. stronger primer strike, the heavier hammer spring makes the hammer push harder against the sear/trigger and it is much of this force that relates into a heaver trigger pull when you use a heavier hammer spring.

    Take the upper off the gun so you can see the hammer. Cock the hammer and pull the trigger (but don't let the hammer fly all the forward and hit the lower!) . The hammer is likely to move backwards just a bit before it releases and falls. It is that movement of the sear out of the hammer notch that you are over coming when you pull the trigger.

    A match trigger with a near perfect sear angle will not have as much rearward movement of the hammer, but you still have the force of the hammer/sear interaction to overcome so again (all other things being equal) a heavier hammer spring = heavier trigger pull
    Last edited: Feb 11, 2013
  3. mwezell

    mwezell 12 pointer

    Jan 22, 2006
    Auburn, KY

Share This Page