Trigger Slap and Doubling Trouble Shooting

7/29/2019 Trigger Slap and Doubling Trouble Shooting

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Trigger Slap and Doubling.

First, a few caveats:

This information is provided for your enlightenment.Any modifications you perform, you do so at your

own risk.

The images shown here are drawn for relational

interaction, and not drawn to exact scale. I have not

attempted to replicate exact scale due to the large

variations in AK dimensions.

Trigger slap is the sensation of the triggerrebounding or "slapping" the shooter's trigger fingerduring firing. The sensation is a sharp, abruptforward jolt from the trigger when the rifledischarges. It can be consistent with every shot orintermittent, sometimes favoring one type of


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ammunition. For this reason, it's easy to misdiagnosethis as an ammunition problem.

Trigger slap occurs when there's insufficientclearance between the hammer, trigger and thedisconnector. When this happens, the force of theresetting hammer is transferred into the triggerthrough the disconnector, causing the trigger toabruptly "slap" forward.

Doubling is when the rifle fires more than one shotwith a single pull of the trigger, and the rifle is notequipped for full auto fire. Sometimes the shootermay discover the hammer resting on the firing pin(released or fired position) on a loaded chamber.Pulling the bolt carrier back far enough to reset thehammer will often result in a successful discharge.

All of these common symptoms are caused by aminor defect in the disconnector, located in the firecontrol group (FCG). Fortunately it's often the resultof too much material, so removing the excess willusually correct the problem.

First, we'll explore why the problems are occurring,and then we'll cover how too fix it without replacing abunch of parts.


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(See diagram) The disconnector rides on the sameshaft as the trigger and is spring loaded forward. Itacts like a see-saw and tilts forward until the forwardpad rests on the trigger casting. Note that all pointson the disconnector will execute a radial path around

the trigger pivot pin (common axis). This will becomeimportant later.

During firing, the hammer retreats in a circular pathback toward the trigger. Since the trigger has alreadybeen pulled and cannot retain the hammer, thedisconnector secures the hammer until the trigger is

released. During the process of securing thehammer, the hammer presses the disconnector backagainst disconnector spring pressure. The hammerovercomes the disconnector and spring, and thedisconnector snaps back into position after thehammer passes, capturing the hammer.


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When the shooter releases the trigger, thedisconnector releases the hammer, and the triggers

hammer hook now controls the hammer.

The aperture or opening gap between thedisconnector and trigger hook must be slightlysmaller than the hammers arresting pads. If not, thedisconnector or trigger will fail to catch the hammerresulting in doubling, or a released hammer on aloaded chamber. In this diagram, A represents theaperture size and B represents the hammerdimension.


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If the disconnector hook sits too far back, it will notconsistently arrest hammer movement, allowing the

hammer to ride up on the bolt during closure, ordelaying the hammer briefly and subsequentlyreleasing it before reset. This results in the doublingor dead hammer symptom, and is caused by toomuch material left on the forward pad of thedisconnector.

With trigger slap, the disconnector isnt able toretreat far enough back to allow the hammer to pass,so the disconnector pushes the trigger out of theway. The trigger transfers this motion into theshooters finger, creating the sensation of slap.


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Fixing doubling:

You can correct this by replacing the disconnector, orby removing a small amount of material from theforward disconnector pad. The least amount ofmaterial removal that produces satisfactoryperformance is the correct amount. And, don't beseduced by the "more is better" philosophy. If alittle's good, more isn't better. Don't take off more

than necessary, or the disconnector hook may resttoo far forward and actually try to block the hammer.If this happens, you'll need a new disconnector hook.

The least amount of material removal that producessatisfactory performance is the correct amount.


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Fixing slap:

If there's too much material on the rear disconnectorpad, it will lack adequate clearance between the bolt

carrier, disconnector and trigger. This results in achain collision between the bolt carrier, disconnectorand the trigger. The energy is then transferred intothe shooter's finger, producing the "slap" sensation.

This can be corrected by removing just enoughmaterial on the rear of the disconnector near thespring well. Remove only enough to allow properclearance, no more.

In the next diagram, note the colors. Blue is the areawhere you want to remove a small amount ofmaterial to correct doubling, and removing materialfrom the red area helps correct trigger slap.

Typical Kalashnikov disconnectors (images takenfrom various internet sources)


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Typical semi-auto disconnector

Typical full-auto disconnector

Trigger Slap and Doubling Trouble Shooting

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