HK Variants Explained - LEM vs Multifunction Levers vs Rear Decockers

Close up look at HK’s various safety systems for their hammer fired guns.
Full list below.
Note variant numbers are not consistent across all models.
USP variants
Variants 1 and 2 (double action/single action, decocking and safety lever)
Variants 1 (lever on left) and 2 (lever on right) allow the user to carry the pistol in a single-action mode (cocked and locked) with the manual safety engaged. This same pistol, without modification, can be carried in double-action mode, with or without the manual safety engaged, and with the benefit of a decocking lever.
Variants 3 and 4 (double action/single action, decocking lever, but no safety)
Variants 3 (lever on left) and 4 (lever on right) provide the user with a frame-mounted decocking lever that does not have the "safe" position. This combination only allows the hammer to be lowered from SA position to DA position. It does not provide the "safe" position to prevent the pistol from firing when the trigger is pulled.
Variants 5 and 6 (double action only, with safety lever)
Variants 5 (lever on left) and 6 (lever on right) operate as double-action-only pistols, with a bobbed hammer always returning to the DA position (forward) after each shot is fired. To fire each shot, the trigger must be pulled through the smooth DA trigger pull. Variants 5 and 6 have a manual safety lever.
Variant 7 (Law Enforcement Modification, no control lever)
Developed for the U.S. government, the Law Enforcement Modification (LEM) is a double-action only model with a unique trigger mechanism. This mechanism improves the double-action trigger performance and reduces the weight of the double-action trigger pull to 8 pounds-force (36 N), uses a stronger hammer spring, and shortens the trigger reset.
Variant 8
Never produced.
Variants 9 and 10 (double-action/single-action, safety lever, but no decocker)
Variants 9 (lever on left) and 10 (lever on right) allow the shooter to carry the pistol in a single-action mode (cocked and locked) with the manual safety engaged. This same pistol, without modification, can be carried in double-action mode (hammer down), with or without the manual safety engaged. The double-action mode offers a second-strike/double-action capability in case of a misfire. The control lever has no decocking function on variants 9 and 10, so one would have to lower the hammer manually (or keep the safety on, remove the magazine, and eject any round in the chamber before lowering the hammer).
P2000 variants
V0: CDA/DA trigger system. The CDA aka LEM trigger is a dual-stage trigger that always fires from a hammer down DA mode, but has an internal mechanism that is cocked with each cycle of the action. It provides a cocked double-action trigger pull of 20 N (4.5 lbf) (+4/-2 N) and an uncocked double-action trigger pull of 51 N (11.5 lbf) (±5 N).
V1: Same as V0, but hammer has no spur, and there is no decocker button; therefore, the only way to release the cocked mainspring is to pull the trigger over the empty chamber.
V2: Same as V1 but with an increased trigger weight. The trigger pull is 32.5 N (7.3 lbf) (±2.5 N).
V3: SA/DA trigger with a decocking lever mounted at the posterior of the slide to the left of the spurred hammer. Single-action trigger pull of 20 N (4.5 lbf) (+4/-2 N), double-action trigger pull - 51 N (11.5 lbf) (±5 N).
V4: Same as V1 and V2 but with a mid-range trigger pull of 27.5 N (6.2 lbf) (±2.5 N).
V5: Double-action only (DAO) trigger system. Trigger pull of 36 N (8.1 lbf) (±3 N).
P30 variants
Variant Action Trigger pull Trigger travel Notes
V0 CDA aka LEM 51 N (11.5 lbf) (DA)
20 N (4.5 lbf) (CDA) 14 mm (0.55 in) Combat Defensive Action (CDA) aka Law Enforcement Modification (LEM):
Exposed two-piece hammer with spur. It uses a V1-type "light" Trigger Return Spring (TRS). The cocking piece can be decocked by pressing the decocker button, located at the rear of the slide, next to the hammer. This spurred hammer-version was designed for the European market.
V1 CDA aka LEM 20 N (4.5 lbf) 14 mm (0.55 in) Same as V0, but the hammer has no spur, and there is no decocker button; therefore, the only way to release the cocked mainspring is to pull the trigger over the empty chamber.
Employing a light Trigger Return Spring (TRS), it is referred to as "light LEM."
V2 CDA aka LEM 32.5 N (7.3 lbf) 14 mm (0.55 in) Same as V1, with a heavy Trigger Return Spring (TRS)
Employing a heavy Trigger Return Spring (TRS), it is referred to as "heavy LEM." The heavier TRS provides a more clean trigger reset while providing comfort to people concerned about accidentally discharging their firearm under stress. This version is no longer directly purchasable in the USA.
V3 DA/SA 51 N (11.5 lbf) (DA)
20 N (4.5 lbf) (SA) 14 mm (0.55 in) (DA)
7 mm (0.28 in) (SA) Conventional DA/SA unit with single-piece, spurred hammer and decocker button at the rear of the slide, next to the hammer.
V4 CDA aka LEM 27.5 N (6.2 lbf) 14 mm (0.55 in)

[@fridayblues216]

I own that HK .40cal USP V1. I like this version most among all the ones featured here because of its size. Awesome gun!!!

[@user-xk1sy9pl6z]

As a left-handed shooter, I have my HK45c rigged in variant 10. It works quite well for me in the cocked-and-locked position. My P30s are all variant 3 mostly with safety. Decocking with the left thumb is rather challenging, but it does work. I had an HK45t with LEM, but it just wasn't right for me. I do appreciate the variant explanation, keep the HK love flowing!

[@TheArkansasGunGuy]

HK 4eva!!! Ha. Thank you for watching my channel. I’m still sad that I could not get better w the LEM. Maybe I just needed to practice more. Great idea - I’m just not a good enough shot!

[@conspicuouslyinconspicuous427]

I installed the 5-6 plate in my USP converting it to cocked & locked only, 1911 style. As I’ve said in one of your previous vid’s, I could go for an extended safety but the guy at Teufelshund Tactical said some people are installing the HK45 safety (it’s interchangeable with minor fitting) and getting good results.

[@LUIZS87]

V3 is the last one

[@TheArkansasGunGuy]

Thank you!!! and thank you for watching!!!