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Discussion Starter · #1 ·
I have an AE date coded USP9 V1 and I recently purchased the LEM kit from CDNN. I wanted to get the lighter LEM trigger pull, so I decided to keep the hammer spring, the firing pin block spring and the trigger rebound spring from the V1 and only use the cocking piece spring that came with the kit.

A couple of questions:
1) how is the cocking piece spring supposed to fit? One "leg" of the spring points towards the muzzle, but does the other "leg" point up or down? Also, from left to right, is the correct order the cocking piece spring and then the hammer/cocking piece combo? Thirdly, if that's the correct order, then the "legs" of the cocking piece spring should point to the right, correct?

2) What's the trigger supposed to feel like? I think I put the cocking piece spring in upside down. So I'm getting 2 trigger pulls: a really light one when the hammer is cocked back, and a really heavy one when I'm dry firing. This is wrong, right? It should be the same trigger pull every time, regardless of whether I'm dry firing without the slide moving or shooting live ammo with the slide moving.

3) The hammer is moving somewhat sluggishly, but I suspect that's because I put the cocking piece spring on upside down?

Any thoughts would be appreciated. Thanks in advance.
 

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2. You should be getting two trigger pulls, a ~4.5lbs one with the slide racked and a ~12lbs one when the slide isn't racked. Not sure about the install.
 

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I just found that little bit curious, so the LEM isn't a "true" double action in that it forces the hammer all the way? It retains some of the hammer spring tension after you rack the slide?
 

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Look at my post on the install. It is very clear where the legs are supposed to go.
The right leg fits in the small notch on the muzzle face of the hammer, the left leg points toward the muzzle. link

It is a true DAO pull as much as the Glock is a true DAO pull. Cycling the action preloads the hammer spring so you get the light pull. You finish loading up the hammer by pulling the trigger and get the light pull, but if you do not rack the slide between drops when dry firing then you must fully load the hammer with the trigger. That is not how the gun operates when live firing since the cycling of the slide preloads the hammer.
 

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Discussion Starter · #5 ·
I looked at Big Bore's instructions and re-installed the cocking piece spring in the correct position. The hammer behaves a lot better now, thanks!
 
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