LEM kit

[The Legend]

Could somebody please explain to me in the simpliest terms possible, what exactly a LEM kit is and its advantages and why and how to install one.

Pardon my ignorance.

[MakeMineA10mm]

LEM stands for "Law Enforcement Module" which creates a Glock-like (not exactly, but close) DAO trigger pull. It does this through partially pre-cocking the hammer/trigger mechanism, so that when you pull the trigger, the long beginning part of the pull is very light, because it is just the resistence of the mainspring and trigger return spring. Then, the pull gets a little heavier towards the end. Overall, it's still lighter than a standard double-action pull, because by the time the trigger pull gets heavy on the LEM, it's at the point where your finger and the trigger mechanism has good mechanical advantage, whereas with a standard DA pull, you have to overcome the pressure of cocking the hammer fully.

Installation instructions are included with the kit, IF you get the kit from CDNN, because they've typed up the instructions - HK assumes you know what you're doing, if you order it...

As far as why to do it... Well, it converts the mechanism to a Glock-like mechanism, but keeps the hammer, instead of going to a striker-fired system, like the Glock. This allows easier trigger pull than traditional DA, with the trigger pull being the same every shot (no DA first shot and then SA remainder of shots), and elimination of the manual safety/de-cocker mechanism. Overall, just like a Glock, it's an easier trigger to learn and master and there's no "first round flinch" (which is really not a flinch, but the person not being trained well enough to control the heavy, gritty DA pull on traditional DA auto pistols).

[Chowser]

If you get it, there are more detailed instructions with pics over at hkpro.com

I bought and installed over a dozen of them a few years back for a neighboring agency that issues the USP .45/compact (same kit for full size or compact USP).

Their issue guns was all V7 (DAO) and the SWAT team guys were allowed to switch to LEM. I did the install with a 5/6 lb trigger pull.