[PaulC]

What would happen if the precocked hammer spring were to have a mechanical failure and be released. Would this still transfer enough energy to the hammer to make the gun go off even if the hammer is in the down position?

 

[eddieb]

The hammer will never make it to the firing pin. The catch will stop the hammer. The only time the hammer would hit the firing pin is if the hammer is pulled, disabling the catch.

 

[PaulC]

Ahhh I see. Looks like I need to study the LEM trigger system some more. Thanks for the reply.

 

[ptoemmes]

This is as good a thread to hijack (sorry) as the one on a LEM decocker, but I think this is related.

In this post from 2008, Big Bore explains the LEM trigger components: http://www.hkpro.com/forum/hk-handgun-talk/83102-lem-trigger.html#post617582

I believe for the HK45/45c and perhaps also the USPs there is only standard (heavy) and optional light LEM. For the P series there may be three LEM weights with their own variant identifiers. And, there is the Todd Green Special "spring combination".

This is what I am interested in understanding better.

For the HK45/45c, I assume "for the most part" it's the springs against which you encounter pull resistance and get the the different "trigger weights".

With a round chambered, since the hammer spring is fully compressed and the internal hammer of the LEM two-piece hammer is fully cocked it seems to me that it's the TRS, FPBS, and maybe a little from the LEM cocking piece spring that provides the resistance during the "stage 1" take-up pull (also external trigger (spur) "cock" positioning - guessing too that the catch is moved as well) and then the final pull (trigger weight) when the external (spur) trigger falls and the gun fires.

For light LEM in the 45/45c you retain the stock hammer spring and TRS. I also assume later models already have the lighter (stock) FPBS so no spring change there. For standard (heavy) LEM you replace the TRS with the heavy TRS spring and hammer spring from the kit.

Is it true that, since the hammer springs is fully compressed anyway when a round is chambered (other than after a no fire strike), that the hammer spring has no impact on the (final) trigger pull weight?

If true, then it's just the TRS, FPBS, and maybe a smidge from the LEM cocking spring that accounts for the differences in standard and light LEM final trigger pull weight

This is admittedly academic, but I ask because I have seen tables showing different trigger pull weights for standard and light LEM (understandable), but also for TGS which I believe calls for the heavier TRS with light (stock) FPBS, and stock hammer spring.

I'd think the trigger weight of TGS would not be all that different - or different at all - from standard (heavy LEM). No, I'd probably be wrong in this thinking, but then that's why I am asking.

Thanks,

Pete

PS
I have a 45c with standard LEM. Just want to know more about the "mechanics" of what is going on.