Thank you. Now... question... can you carry it "cocked and locked", like a 1911?
With an LEM trigger, No. There is no safety and no decocker. It is just the trigger. Again, like a glock or Springfield XD. Proper muzzle discipline and trigger control (finger off trigger until ready to shoot) acts as your safety.
But unlike the glock or XD the amount of force required to press the trigger is higher depending on which LEM trigger you get and the length of pull for the trigger is longer. It was designed to be a quick and simple combat trigger. Draw, aim, shoot. No more no less. No extra levers to have to remember to use under stress. Even with a DA/SA pistol with a decocker like on a SIG or Beretta M9, lots of times even trained people will forget to decock after their string of fire and then they either move or try to reholster with the gun still in SA mode which is very dangerous. Like re holstering a 1911 without flipping the safety back on.
Second question... if you can carry it cocked and locked, and you snick the safety off, is there a danger of going too far with the safety lever, and de-cocking the gun?
No, you have to move the safety in the opposite direction to de-cock.
Only HK pistols that are DA/SA will have manual safety levers and de-cockers. There are two different styles.
On the older HK pistols, such as the older MK23, or the USP or USP compact series the safety and decocker were built into the same lever. It was in the same position roughly as a 1911 on the left side of the gun with the rotational pin of the safety/decocker towards the rear of the gun.
So for example for a right handed shooter you would use your right thumb to move the safety lever UP just a little bit for safe and down to keep it level for fire Just like on a 1911 but with less distance to travel. The difference between the two was minimal and very fast to get into action and there was a very distinctive.... I wouldn't say "click" but you could definitely feel the difference when you dis/engaged the safety from the two positions. It snapped into place I guess you could say.
Now to de-cock the gun to get it from SA back to DA you would instead use your same thumb and press DOWN on it so the forward part of the same lever would sweep down and counter clockwise. This had to be a very deliberate move (deliberate does not mean hard). The travel distance of the lever you would have to press/sweep down to de-cock was about 2x-3x the distance than to move it up to safe and fire. And you had to use some measure of force (again not so much that it was a pain in the butt, but enough so that you would not accidentally de-cock when you didnt want to) to do it.
What is cool about the DA/SA HK pistols is that you can safely carry the gun in three different ways depending on personal preference.
1. De-cocked in DA, safety on
2. De-cocked in DA safety off (this was how I carried mine as the DA trigger is very heavy)
3. "Cocked and locked" in SA but with the safety on just like a 1911.
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Now on all of the newer model HK guns such as the P2000, P2000SK, P30, HK45, HK45C etc, for the guns that are DA/SA they will still have a safety similar to the older ones I just described. So basically a shorter travel 1911-esq type safety.
The difference being in the new models is that they moved the de-cocker to the rear of the slide just to the left of the hammer. As in it is right on the rear end plate of the slide that literally faces you as you aim your gun and look down the sights. It is a small button that you engage with your thumb.
It takes a little getting used too but after a trip to the range and a couple boxes of ammo you get used to it.
Again on the LEM HK guns there is no safety or de-cocker.
As for the LEM trigger it is usually one of those things that people love or hate. *shrugs. I like it personally but it is different and unique no doubt and if you ever get a chance to shoot one first to try out that would be what I recommend.
Now that I think about it I suppose it is sort of similar to a Ruger LCR trigger in a way but smoother. Not quite but you sorta get the idea maybe.
Hope that helps if you have any other questions ask away and I'll try to answer them. if you look on youtube for videos like "HK USP compact review" or "HK LEM trigger" you can probably find some viewable examples of how the safety/de-cocker/triggers work.