A mini study of two stage triggers

Discussion in 'Technical Questions & Information' started by LDBennett, Oct 4, 2008.

  1. LDBennett

    LDBennett Well-Known Member

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    Over the last 20 years or so I have done many trigger jobs and studied the design of those triggers and those of many other guns. I have recently come to the conclusion that the Europeans may have found a superior trigger system design with their two stage trigger designs. A recent purchase of a Benelli Olympic style pistol showed me how they do it and why it is superior to other systems when a light, crisp, and safe let off of the trigger is required.

    Conventional trigger system use the sear to hold back the hammer or striker. To get a creep free and light single stage trigger you have to poise the sear near to the edge of the engagement surface (to reduce felt creep). To keep it safe the sear engagement angles have to be such that the force of the trigger pull has to move the hammer/striker back against the hammer/striker spring to some degree (called hammer cam back). Finding the safe point between the amount of engagement, the sear engagement angles, and the spring forces to achieve a light trigger pull is a tug of war. When light enough it is not safe enough and when safe enough it is not light enough or includes too much felt creep.

    The Benelli and several other European trigger systems use a two stage approach. The engagement of the sear is huge for safety when not using the trigger. The first stage of trigger pull takes the sear right up to the edge of its engagement shelf where an increase in force above that required to get to that point sets the gun off. The engagement shelf is micro polished and extremely hard so the first stage is so smooth there is no indication that the sear is actually moving on a sear engagement surface. The angles are such that there is no hammer cam back action as needed on a safe trigger of the typical American variety. All this is because the sear engagement initially is huge, maybe ten to 100 times the standard American trigger system after a competent trigger job. The first stage trigger motion moves it from this safe place to the edge of the engagement surface where the second stage of increased pull level takes over for the very small last bit of trigger motion for firing the gun. My Anschutz rifle in 22LR appears to have the same trigger action as does my Sig Trailside which is based on a Hammerli Olympic target pistol.

    While the mechanisms are completely different in implementation, the classic Mauser 98 and other military rifles around the world use a similar system of two stages. The Mauser uses two humps on the trigger to actuate the sear. The first hump gives a light pull that moves the sear to the edge of its engagement surface. The second hump decreases the trigger's mechanical advantage over the sear (for a heavier second stage) that completes the pull with only a short second stage of pull. The resultant trigger is safe when not being pulled, gives a tactile feel when you get to the second stage, and has little to no creep for the second stage. Good feel and safe...that's the answer not "hair triggers" that sometimes create very unsafe guns for the user and those around him.

    American manufactures and American shooters need these two stage triggers and American shooters need to learn to use them rather than the unsafe super light competition triggers so many shooters here in America seem to prefer. I am convinced that if used by these shooters enough then they would eventually see that two stage triggers are very much superior to the triggers we profess to need (light, creep free, single stage triggers). Over the last few years I have been converted!

    Any other thoughts on this matter?

    LDBennett
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