Heckler&Koch HK45 COMPACT TACTICAL - Manual (Page 6)

10 11
HK45 & HK45 Compact
The flat spring provides constant pressure on the front of the sear. The cocking
piece rotates until the sear lug located on the lower left hand side of the
cocking pieces engages and is held by the sear. The cocking piece spring
ensures that the hammer is always in the up position. The cocking piece spring
is needed to ensure that the hammer is always in the “up” position.
When the trigger is pulled, the trigger bar, which is mounted on the right hand
side of the trigger, moves forward. The lug on rear of the trigger bar engages
and then rotates the hammer forward as well as pivoting the sear actuator latch
upwards. The hook located on the bottom of the sear actuator latch engages
the roll pin located on the bottom of the sear. The spring tension of the flat
spring is overcome and the sear disengages from the cocking piece, allowing
the hammer to strike the back of the firing pin.
This unique pre-cocked hammer system combines the advantages of a cocked
striker fire component (constant level of trigger pull and short, constant trigger
travel from first to last round fired). This ensures an extremely safe pistol with
regard to unintended firing.
There are currently two trigger pull weight options available for the LEM
system:
• Standard Trigger Pull (approximately 7.5 to 8.5 lbs)
• Light Trigger Pull (approximately 4.5 to 5.5 lbs)
Traditional Double Action Only (DAO)
If, for any reason, the slide does not recoil to the rear after firing (i.e., failure
to fire), the LEM features a traditional DAO trigger pull. In this situation, the
trigger is pulled and the trigger bar moves forward engaging and rotating the
hammer. In the case of a traditional DAO trigger pull, the hammer strut spring
must by compressed by the operator pulling the trigger whereas in the LEM
mode the hammer strut spring is compressed by the slide passing over the
hammer.
The traditional DAO was incorporated as a back up system that allows the
operator to re-engage the trigger (albeit with a heavier trigger pull). If the
traditional DAO system were not added to the LEM design, the operator would
be forced to rack the slide to the rear to recock the hammer before attempting
a follow-up shot.
NOTE: The LEM system will ALWAYS be activated by the slide passing over
the hammer. The only time the Traditional DAO system is activated is when
the slide does not recoil out of battery. Examples of such a situation include
a weak primer strike and/or failure for the cartridge to ignite.
The weight of the trigger pull can be adjusted by an armorer by replacing or
exchanging the firing pin block spring and trigger spring.
Special LEM Considerations and the HK Lock-Out Device
On HK45 Pistols that have LEM parts and HK Lock-Out Device installed (see
page 11), the HK Lock-Out Device cannot be engaged (locked) if the Law
Enforcement Modification cocking piece is cocked and the hammer spring is
compressed. To engage the HK Lock-Out Device on pistols fitted with LEM
parts the pressure stored in the hammer spring must first be released. You
must CLEAR the pistol (see inside cover), ensure that it is unloaded and safe
and dry fire the pistol once to release the cocking piece and the tension on the
hammer spring before you can engage the HK Lock-Out Device.
Long Term Pistol Storage
Anytime the slide is moved fully rearward on the HK45 Pistol fitted with LEM
parts the hammer spring is compressed and held in that position until the
cocking piece is released by pulling the trigger on the pistol. Therefore for
long-term storage (more than 1 year) it is suggested that the pistol first be
CLEARED, and made safe, then pointed in a safe direction and dry fired to
release pressure on the hammer spring to maintain its life span.
Firing the HK45 equipped with LEM
All rounds are fired in the LEM DAO mode of fire as they are in conventional
DA or DAO handguns. When pulling the trigger rearward you will first feel a
relatively long length of free travel (slack) and then a second stage of heavier
but consistent pull that actually releases the hammer and fires the pistol. This
slack can and should be safely taken up, once the pistol is pointed at the
target, to enhance trigger pull consistency.
In addition to providing an improved DAO trigger pull, the LEM also provides
a very short trigger reset distance to enhance the speed of multiple or follow-
up shots (forward movement of the trigger before firing once again is possible)
and allows for double-strike capability to restrike an unfired round without
manipulation of the slide, as is required in some conventional DA only or striker
fired handguns.
WARNING: Do not place your finger on the trigger or within the trigger
guard until you have made a conscious decision to fire the pistol. If you need
additional information, please contact your customer service representative
at HK Customer Service at (706) 568-1906.
SECTION 1