by Todd Louis Green
The issue arises quite often: compare the Heckler & Koch LEM (“Law Enforcement Modification”) trigger to the SIG-Sauer DAK (“Double Action Kellerman” … named for its inventor). Here is my take on the subject after becoming fairly well acquainted with both.
HK LEM
The HK LEM is basically artifice. It uses a two-piece hammer, one part internal and one part external. When the slide is racked (loading the gun or during the firing cycle), the mainspring is compressed and kept in place as with any single action mechanism. However, the external part of the hammer moves fully forward and so does the trigger. In essence you have a cocked pistol that doesn’t look cocked.
The first shot is long like a traditional double action pull, but it’s not any heavier than subsequent trigger pulls. The reset is certainly longer than most striker-fired guns or a 1911, but it’s only about a third of the total trigger travel arc. Three different configurations are available:
V1: nominal 4.5# trigger pull; uses standard trigger return spring and standard firing pin block spring … this is essentially the standard P30 SA trigger pull from the DA/SA variant
V2: nominal 7.3# trigger pull; uses extra strength trigger return spring and extra strength firing pin block spring … the one example I have measured 7# 10oz out of the box and has dropped to 7# 8oz after 1,000 rounds
V4: nominal 6.1# trigger pull; uses the extra strength trigger return spring but a standard firing pin block spring … for reasons explained below, I believe this is probably the best option
The one I’m most familiar with is the V4. The extra strength trigger return spring plays a tremendous role in counteracting the long reset. Obviously, it’s the speed at which you manipulate the trigger rather than simply the distance which determines how fast your next shot will discharge. While moving a longer distance would seem slower, the stronger trigger return spring literally slams the trigger to the reset point faster than you could move your finger alone. Will it be as fast for blind “for the fun of it” rapid fire? Probably not. But I was pulling .20 splits give or take a couple hundredths after just a few boxes of ammo.
The extra power firing pin block spring serves no purpose but to increase the trigger pull weight, so I’m planning on replacing mine with the lighter one to get about a 6# trigger pull, which I find is close to ideal for a practical gun.
SIG DAK
While my experience with the LEM did not begin until 2009, my use of the DAK is extensive. In fact, I was the first person in the US (and probably in the world) to put one through its paces as a dedicated high-level training gun for many months when it was first imported. For quite a while, I had probably fired more rounds through a DAK than anyone outside a test range. I even wrote the lesson plan & taught SIG’s first DAK transition class (for a large federal agency).
The SIG DAK is a genuine Double Action Only design and (prior to the SIG P250) had probably the lightest true DAO trigger pull on the market. Unlike the LEM, when the SIG DAK is at rest, the mainspring is not compressed any more than it would be in a decocked DA/SA SIG. The lighter trigger pull is achieved solely through changes to the trigger bar and some other internal parts which allow greater leverage.
When it was first released, the DAK had a nominal trigger pull of three kilos (6.6#). However, it never really quite worked out that way. For example, when we submitted the guns to DHS/ICE for testing in 2004, we called it a 7.2# trigger pull.
Because the size of the gun determines how long the trigger bar can be and thus how much leverage you can achieve, the P229 trigger was always a little heavier than the P226 by one quarter to one half a pound. The P239 DAK, being so short, has a trigger pull almost identical to the standard DA stroke for that gun. And the P220, which uses different internal dimensions, is about the same as the P229. Then, after a couple years on the market, it was determined that the DAK struggled with non-toxic primers. So a new spring, indicated by red paint, was introduced to provide a stronger primer strike. In my experience, the typical DAK trigger right now is around 7.5# +/- half a pound.
Then there is the reset. The DAK does not use a rebounding hammer like a standard (DA/SA) SIG. Therefore, it relies on the slide cycling to place the gun in what SIG calls the ‘safety notch’ or firing position. In order to provide restrike capability — which SIG considers a worthwhile feature for a combat gun — the DAK needed a way to cock the trigger when it was not in the safety notch position. The result is that, instead of being a simple “true” DAO with a full length reset, there is also an intermediate reset on a DAK. This intermediate reset, which does not benefit from the full leverage of the modified DAK mechanism, is about 2# heavier than the ordinary trigger pull. So you can either release the trigger all the way out (like a DA revolver) and get that same ~7.5# trigger pull, or you can reset it half way and get ~9.5# trigger pull on follow up shots.
In my experience, releasing the trigger all the way forward makes for much better results. In fact, I taught — and convinced many people at SIG — that the “intermediate” reset was really just there to save you if you short stroked the trigger … while you should let the trigger all the way forward, the gun would protect you from yourself if you didn’t. It sounded very tactical. But eventually people started to complain about how long the reset was and SIG changed course, instead saying that it was simply the shooter’s choice as to which reset he should use. Last I knew, the SIG Academy taught folks to use the shorter intermediate reset.
Comparison
Both actions are very smooth and manageable from a marksmanship standpoint so long as you do not try to anticipate the shot (which can take some getting used to for Glock & 1911 shooters).
Because the trigger on the DAK & LEM will move all the way forward between shots if you let it, you never run the risk of losing contact with the trigger between shots. This means much less chance of slapping the trigger when shooting at maximum speed. So for example, while my splits were a little slower with the DAK than with a DA/SA SIG (especially using the Short Reset Trigger version), I was much less likely to throw a shot with the DAK.
The LEM wins for me because of the reset. I can use a “short” (relatively speaking) reset while keeping a true consistent trigger pull from shot to shot. Whereas the DAK is like shooting a DA revolver (not counting the intermediate reset), the LEM is much more like a 2-stage AR trigger … a comparison I stole from pistol-training.com contributor Tim Slemp. The LEM also has the option for the extra strength trigger return spring, which further enhances the reset and resultant speed.
Both systems will certainly work for the majority of shooters. Between the two, though, the HK LEM is the one I shoot best.
About the author: Todd Louis Green has worked in the firearms industry since 1998, including instructing for the NRA Range, Beretta, and SIG-Sauer. He has over 1,000 hours of formal firearms and combatives training. A 3-time “Advanced” rated shooter at Rogers Shooting School, Todd is also a graduate of the NRA Tactical Pistol Instructor Development program and a 3 division Master-ranked IDPA competitor. Todd is a certified Beretta, Glock, Heckler & Koch, SIG-Sauer, and Smith & Wesson armorer; certified Simunition force-on-force instructor; and certified Emergency First Responder. He is a long time member of IALEFI, IDPA, and USPSA.