Sequential Nail Guns

Sequential nail guns are pneumatic guns that require the nose of the gun to be depressed before the trigger can be pulled in order to fire.


A pneumatic nail gun with a sequential-trip mode is an engineering control that can reduce inadvertent nail discharges.  By having a restrictive trigger, users must first press the nose of the nail gun onto a work surface before the trigger can be activated to release a nail.

Pneumatic nail guns, often used during residential construction and wood-product fabrication, rapidly sink nails into wood and are easy to use.  Contact-trip or sequential-trip mode are the two basic trigger mechanisms used in pneumatic nailers.

In the contact-trip mode, also known as bump mode, the trigger can be pulled prior to setting the nose of the nail gun onto the workpiece. Each time the nailer is depressed against the workpiece, a nail is fired while the trigger is held. This allows the "bumping" of the nail gun which can rapidly and continuously drive nails along the workpiece.  Because this mode will fire when the nose touches anything, this can result in the unintentional firing of nails.

In contrast, in the sequential-trip mode, also known as a restrictive trigger, the nose of the nail gun must be firmly pressed against the workpiece before the trigger can be pulled. After one nail is fired, the trigger must be released before the next nailing cycle can begin.

Risks Addressed:

Punctures from nail gun nails are the leading cause of 'struck by' injuries in residential carpentry and account for nearly 40,000 annual visits to U.S. emergency departments. The most common type of puncture injuries are to the hands and fingers.  Punctures are typically piercings or perforations through the skin.  Sometimes, even the fragments of tools or materials may bury under the skin layer.  Nail guns with a sequential-trip mode makes firing a two-step process thereby reducing unintentional nail discharges.

How Risks are Reduced:

Nailers will typically recoil after discharging nails.  For a contact-trip nailer, if the nose of the gun contacts the surface element or a previously placed nail, this can result in an inadvertent discharging, ricocheting and having airborne nails.  Nailers with contact triggers are also susceptible to double-firing, especially when trying to accurately place the nailer against the work piece in activities such as "toe-nailing."  It is also natural to hold the gun with a finger on the trigger because that is where the center of gravity is located.  Hence, the second firing can occur well before the users are able to take their fingers off the triggers.

Using the sequential-trip mode reduces the possibility of discharging a nail when the nose of the nail gun is accidentally bumped against yourself or others.

Injury surveillance in the residential construction industry has indicated that approximately 65% to 69% of injuries from framing nail guns with contact-trip triggers likely could be prevented through use of a sequential-trip trigger. Furthermore, a 55% decline in acute injury rates has been demonstrated through use of sequential triggering and training.

Additional Considerations:

For more information, please visit:

NailGunSafety: The Facts -

eLCOSH Hazard Alert: Nail Guns -

eLCOSH 'Death in the Sierra' video -

eLOCSHO 'Just Driving Down the Street - A Nail Gun Injury' -


Jean Christophe Le, MPH. - CPWR - The Center for Construction Research and Training.

Hazards Addressed:


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Metabo HPT
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Stanley Bostitch
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