In the late 1990’s when I was looking to upgrade the trigger in my Colt AR-15 I spent a large amount of time trying to pick one out. Now keep in mind that that was back in the “ban” era and the pickings were slim. Unlike that of today. Fast forward to today and there be a plethora of triggers and trigger styles to select from. For newer shooters, trying to decipher the differences between trigger styles alone can be daunting.
Done Before We Start
If you’re new to shooting, or you’re assembling your first AR, I urge you to stick with the standard single-stage trigger. If you’re assembling, check out either the ALG ACT, BCM PNT, or the ALG QMS. These are “cleaned” up mil-spec triggers that offer a smoother trigger pull combined with a crisp trigger break over the more standard mil-spec triggers.
The classic triggers will smooth out over time. When you’ve finally burned out your first barrel participating in training courses and structured practice on range days, or you’re at the point of marksmanship that your factory trigger is holding you back in competition, feel free to upgrade the trigger to give you that next step. Until then, jumping right to a high dollar trigger might shortcut your learning process as well as be a possible safety concern.
OK, into the details.
Next to barrels, selecting an AR trigger is the most controversial issue for AR enthusiasts. One does not have to look far on social media and forums to see this. It’s actually frustrating, because so much of it is personal preference, yet everyone will tell you unequivocally that you should get whatever model they like. To add to the mix you have sponsored shooters touting triggers. You have paid “influencers” pushing an agenda when most don’t know how the trigger they’re pushing actually functions or what its downfalls may be for certain applications. Then you have the YouTubers. Don’t get me wrong, there are some valid channels out there with good info but a good majority of it is entertainment or misled information.
This article is less about me telling you what trigger to buy, and more about considerations. It’s about education. It’s about giving you information so that you can make informed decisions based on your requirements.
Be purpose driven
Let the mission drive configuration
Buy Nice or Buy Twice
Never sacrifice dependability for performance
You should always configure your AR and buy your AR trigger and accessories based upon your mission requirements. Are you assembling a SHTF AR, then assemble it to fill the plausible mission requirements that you may need it for. Are you assembling a USPSA PCC comp gun? Then use parts and assemble it to the plausible mission requirements. To shoot USPSA PCC matches and not 3-Gun matches.
Avoid buying components for imaginary scenarios you will never face. And especially don’t buy something because the people of the Instagram, Facebook, or whoever else would think well of it.
When you do make your selection, make sure you’re buying something quality. And no, price doesn’t always equal quality. I don’t typically call out companies, but I’m going to call out two here. For many years back in the 2010 timeframe, the Rock River NM two-stage trigger got very popular as a budget option. Some individuals even used them in match rifles. Yet there were stories everywhere of them wearing out in only a few thousand rounds. Inevitably, people would replace them with another of the same model. For the cost of two of them, they could have bought a single quality trigger that lasted longer than the rifle itself. Fast forward to two years ago, 2018. I purchased an Elftmann 3-Gun trigger. A high end competition cassette style trigger. Out of the box it was bad. The hammer would not correctly fire. It would only go to the drop safety notch when the trigger was pulled. The replacement for it….. bad out of the box too. Same thing. The replacement for that one worked. But it didn’t stay in the gun very long before being retired to the box of shame. Just shows that price does not equal quality.
I did my research on the Elftmann trigger beforehand and I found many documented concerns with the trigger. Instead of following my rules and instinct I decided to order one. Research is something that I recommend to everyone. If something has a decent amount of documented history from lots of different sources, there’s probably a reason why.
Let’s get basic. Let’s discuss the basics of the AR Mil-Spec Fire Control Group.
Trigger – The portion that your finger squeezes during the firing cycle.
Hammer – The portion under the most spring tension; it’s held in place by the sear until the trigger moves out of the way. Once released, spring tension drives the hammer’s mass into the firing pin of the bolt.
Sear – The area where the trigger and hammer interface. This is the forward face of the trigger and the trigger notch on the hammer. When at rest, the tension of the cocked hammer rests on this area and keeps the weapon from firing.
Disconnector – As the weapon fires, the bolt carrier moves rearward and rotates the hammer back towards the cocked position; this process is extremely fast and the disconnector “catches” the hammer so that it does not go forward again.
Hook – A portion of the hammer that the disconnector “catches” during weapon cycle. After cycling and the trigger is “reset”, the disconnector lets go of the hook and the trigger will re-engage the sear.
Hammer Spring– The spring that provides tension to the hammer to move the hammer forward and strike the firing pin when the hammer is released from the trigger. The legs of the hammer spring rest in notches in the trigger pin. The hammer spring legs are what keep the trigger pin retained in the lower receiver.
Trigger Spring– The trigger springs returns the trigger back to the forward position after the trigger is released.
J Spring– This is the spring in the hammer that retains the hammer pin in the receiver.
Single Stage vs Two-Stage AR-15 Triggers
There is a trigger suited to just about any need you might have. The vast majority of rifle triggers fall into one of two categories: single stage and two-stage. Within these categories, there is a variety of styles, weights, trigger shapes, and materials.
Single Stage Triggers
Single stage triggers are the most common type of AR-15 trigger on the market. Nearly every issued M16 or M4 has a single stage trigger. The same can be stated for most LE AR patrol rifles. The vast majority of rifles sold on the civilian market come equipped with a basic mil-spec single stage trigger.
Single stage mil-spec triggers can also have coatings on them to reduce friction and enhance the feel of the trigger pull. Nickel Boron is the most common, and sometimes it is mixed with Teflon. Some manufacturers offer enhanced mil-spec triggers. On these triggers the manufacturer has “cleaned up” the engagement surfaces while also typically applying a coating to the trigger itself. ALG takes their ACT trigger one step further and includes two different hammer springs so that you can changed the trigger pull weight.
Single stage fire control groups can also be fully contained in one housing. These are known as cassette triggers, or drop-in triggers. Some styles of these triggers will allow you to adjust the trigger pull while others are set and do not. Materials used and the design of these will vary by price. One thing to note about cassette style triggers is that they are typically a maintenance intensive unit. In my experiences they do not tolerate being dirty and can cause malfunctions. It is for this reason that I do not recommend a cassette style trigger for defensive or duty rifles. They are not as robust as other styles of triggers and are not well suited for some calibers or AR applications. I’ve had cassette triggers fail in 9mm PCC guns and I’ve seen so many more do the same.
Then there are single stage competition fire control groups like the Hyper Fire brand. Typically these triggers produce a very light and very crisp trigger with very short trigger resets. Some of their triggers do not even resemble a standard fire control group in that they use two long coil spring assemblies as the hammer springs. These springs provide for full power firing strikes while not increasing the trigger pull weight.
Single stage triggers really are everywhere. They are the most common trigger found in an AR.
That doesn’t mean that the single stage is bad. There a many precision and hunting rifles on the market with this type of trigger.
A single stage trigger is basic. There is no or very little slack during the take-up. The full weight of the trigger is already resting on the spring and sear. To fire, the shooter simply overcomes that initial weight.
The trigger engages with the sear. If there is a lot of surface engagement, it feels heavier. The shooter has to “walk” through the sear engagement until it finally releases the hammer. This slight movement as the sear is disengaging is commonly called “creep.”
The distinct click you feel when you reset a trigger after each shot is the disconnector letting go of the hammer hook and the sear reengaging for the next shot.
Uses of the Single Stage Trigger
Single stage triggers are popular due to their quick operation and simple design. All things being equal, a good shooter can probably shoot slightly faster with a single stage trigger. A light/crisp model can be designed to operate safely, but it will add to the cost of the unit. This cost is why a quality single stage is so much more expensive than the standard mil-spec trigger.
Common hunting and precision rifles in the bolt gun world use single stage triggers with light trigger pulls of 4 lbs or less. In order to achieve a crisp trigger pull, there must be a minimum amount of sear engagement. To achieve this the surfaces are usually polished so that the little engagement there is gets smoothly released as the trigger moves. By military standards this light of a trigger pull combined with a low amount of sear engagement was thought to be too dangerous for combat, and therefore the M16 trigger has a large amount of sear engagement combined with a pull weight that is in a range between 5.5 to 8.5 lbs.
As previously stated it is common to find the single stage fire control group in most LE and military guns. You will also find most store bought rack rifles to come equipped with a very basic mil-spec single stage trigger. On the competition side of things you will typically find single stage triggers in the fast and quick shooting games, as well as some competitions such as PRS.
Two Stage Triggers
You know a two-stage trigger immediately by its short and light initial take-up. Or pre-travel. This movement is not the same as “creep.” Once you pull through the pre-travel, you reach a slightly heavier “wall” to overcome before the shot breaks. This is very similar to a striker fired pistol where you prep the trigger to remove the pre-travel before you begin the pull that releases the striker from the trigger bar or connector.
The total weight of the trigger is the sum of both portions of the trigger pull. For instance, a 4.5 lb trigger might have a light 2 lb uptake followed by an additional 2.5 lb “wall.” This provides a bit of safety slack for the rifle to be bumped around as well as a very predictable breakpoint for the shot.
Another benefit of the two-stage trigger is the ability to “prep” the trigger. This is typically performed when very precise shots are required. The shooter looks through the sights, takes the initial slack out of the trigger and rides on the wall. Once ready for the shot, the shooter only needs to gently pull past the remaining wall to fire.
There is a downside to the “prepping” method. With a light second stage, it’s easy for a momentary lapse of focus to cause a premature shot. I’ve missed my intended target mark in the past because of this. Under more stressful situations with a too-light trigger might result in negligent discharges.
Compared to a single stage trigger of the same weight, a two stage trigger will lighter. This is due to the trigger geometry and because of the different spring tensions. On a two stage 4.5 lb trigger, you will pull through the first 2.5 lbs during the take up and feel a notable, but very light, 2.0 lb wall before the shot breaks. In contrast, with a single stage trigger, you will feel all 3.5 lbs up front with no movement (ideally), and then the shot will break.
It should be noted that Geissele manufacturers a couple of two stage triggers that feel like extremely light single stage triggers. This is accomplished through their design. These are competition only triggers though and it is very easy to have negligent discharges via bump fires, multiple bump fires, or by pulling trigger before you’re ready. These fire control groups are definitely ones that inexperienced shooters should not be using.
I’m going to touch on cassette trigger real quick as over the last few years they have gained tremendous ground in popularity. A cassette style trigger is a fire control group that has all of the components contained in one housing. These are also known as “drop in triggers”. The most prevalent advantages of a cassette style trigger is that they are typically easy to install as you don’t have multiple moving parts, spring tensions, and pins to work against when installing it. They typically also provide for lighter pull weights or even an adjustable range of trigger pull weight, and that most drop in triggers also have a clean and crisp trigger break.
All of this sounds amazing right? Not so fast. There are plenty of downfalls too. Let’s touch on a few. Installation is not always just a drop in and go. The fire control group pocket of an AR is designed and machined for proper debris flow using mil-spec style triggers. I have encountered more than one brand of cassette trigger that would not fit in the FCG pocket due to the housing size and design of the cassette trigger. I’ve also had a couple come across my bench where the installer wedged the cassette trigger into place and it caused a hard trigger pull, light primer strikes, and other trigger related concerns. And since I mentioned debris flow, I’ll get it out of the way now. Cassette triggers are more prone to malfunctions from debris getting into the tight tolerances of the internal parts. They are especially prone to locking up due to popped primers and other large debris wedging into internal components of the cassette trigger. Unlike a mil-spec or “regular” two stage trigger you can’t easily remove a cassette style trigger to clear it of debris, and even if you do get it out, dislodging items such as a stuck primer inside of the housing can be a chore. For the above reasons, I will not use a cassette trigger in defensive or duty guns. Most cassette triggers use anti rotation pins. Another piss poor item for a solution that is not needed. But hey, they look cool. The fire control groups pins are meant to rotate in the AR platform when the trigger is pulled. When they do not, two things can occur. Premature wear of the lower receiver and reduced hammer speed which dependent upon a couple of other factors will typically cause light primer strikes and a failure to fire. Another big concern with cassette triggers is their overall durability. They are more prone to malfunctions and breakage. I’ve seen way too many concerns with them, and I’ve personally experienced numerous failures of cassette triggers in range guns. As previously talked about I have been through a few Elftmann triggers, but I have also experienced catastrophic failures with other cassette triggers in competition and range only guns. This has involved hammers breaking, triggers failing to reset, bearing failure in a more expensive style trigger that used bearing surfaces, and even broken housings. Another concern is that not all cassette triggers will work with all selectors on the market. Elftmann is a good example of this. And more recently I put a post of pics on the BRD FB page of a gun that came in with a Velocity cassette trigger and the selector would not move to the safe position. There was not enough operational clearance between the selector and trigger bar of the cassette trigger. This one was able to be hand fitted, but others just will not work. Period.
I could keep going about other downfalls of the cassette triggers but I think that you get the idea. So what use is a cassette trigger good for? Well like a lot of other things in the AR market, it is mainly to take your money and to put form before function. Now with that said there are some uses for cassette style triggers. With the clean trigger break and light trigger pulls that most cassette triggers have, they can be useful for a competition gun. Whether that be PRS, bullseye, benchrest, or 3-Gun. In my experiences an exception to this is in PCC guns. I have broken one cassette trigger in my USPSA PCC gun and installed a different one to see if it was a fluke. I can say that it most likely is not as the current cassette trigger is also on its way to breaking. Blow back PCC guns are hard on FCG’s and other internal parts, and cassette triggers do not have the durability to stand up to constant use in these guns. Cassette triggers can also be a choice for hunting guns. But a couple of things that I would keep in mind. What is the environment of the hunt as well as the weather, and is it a hunt of a lifetime? As previously mentioned cassette triggers can finicky with debris, as well as with temperatures. The type of lubrication used can also be detrimental to them. I once had one come in that would not fire. Upon checking it I found that the hammer moved in slow motion when the trigger was pulled. A certain type of lubrication was used and after sitting for a while it gummed up the internals of the cassette trigger. Another downfall. I could literally count the seconds as I watched the hammer slowly creep from the cocked position to the fired position. So if I was hunting in extreme temps or conditions, or making a hunt of a lifetime for big horn sheep or to Africa, I would not be using a cassette trigger. Bottom line….. if a life depends on the gun I would not be using a cassette trigger.
Competition Style Triggers
Since I touched on cassette triggers I also want to touch on competition oriented triggers such as those made by HyperFire. From the outside, triggers such as these look like and act like a single stage trigger, but the operational mechanisms are so different. Due to extremely light trigger pulls, extremely short to no trigger pre-travel and reset, and due to the complexity of parts I do not recommend that triggers such as these be used in defensive guns or by shooters who’ve not yet mastered trigger control. Triggers like these, as well as the Geissele 3-Gun trigger and other branded competition style triggers make it very easy to have negligent discharges or to unintentionally bump fire. Both which can have serious consequences. On top of that, trigger designs like the HyperFire and Elftmann 3 Gun do not have durability and long sustained use in mind. That’s not what they’re designed for. I’ve broken a number of HyperFire triggers in comp guns with what I consider to be low round counts. So again, let the mission drive configuration and choose appropriately.
Tips for Selecting an AR Trigger
This decision of which fire control group to use is purely personal preference. There are a wide variety on the market that cater to different uses. Just remember to pick one that meets your mission requirements, and remember that most of the time you get what you pay for but that there are exceptions to that.
In contrast, triggers like those from Geissele, ALG Defense, LaRue Tactical, BCM, or some other manufacturers have both an excellent feel and reliability record. Spend some time and do your research ahead of time. If you can, get out and shoot some AR’s that have the triggers that you’re considering. Even better if the AR is set up close to how yours is.
Remember, everything is a compromise. Extra crisp triggers require extra time in machining and tighter QC tolerances, which mean higher cost. Specialized super light triggers work great for target shooting competitions, but a shooter under stress might inadvertently fire it. Or, even worse, poorly designed light triggers may release if the rifle is bumped or dropped. That’s definitely something you don’t want.
Materials and Reliability
So you may be asking… What are some things to look for in a trigger?
Material and Machining Process
The government standard for the M16 fire control group is an investment casting of AISI 8620 steel. For the hammer, AISI 4620 steel is also allowed. The differences between those steel blends aren’t that important. 4620 has a bit more nickel while 8260 has more manganese. Both are good strong steel alloys suitable for casting.
The important thing here is that mil-spec triggers are investment cast. This is a very old method producing complicated metal parts at scale. It is important to note that this is a different process from metal injection molding (MIM). Casting moulds and metal material form along with the casting method are just a few of the differences. Several manufacturers use other materials. For example, LaRue Tactical and Timney both make triggers out of S7 tool steel. While I haven’t seen any in a while, at one time there were some MIM trigger components on the market too.
The bottom line here is that there are a lot of options out there, so do your homework and buy from a quality manufacturer. A well-made trigger in a properly set up gun should last you a long time.
Some people like to use lighter hammer springs in their rifles. This reduces the tension on the sear which is what reduces the trigger pull weight. It also increases your trigger lock time which can also have the effect of light primer strikes due to a decrease in hammer speed. This is one reason why some individuals will also cut the hammer to reduce mass, which creates another set of concerns. Another side effect of a lighter hammer spring that most people do not consider is that it affects the timing of the AR. The reduced tension requires less effort by the BCG to move the hammer downward to reset. This decrease in effort results in a slight increase in BCG velocity. While it may be minute it is still important to note. I suggest against anything less than a full power mil-spec hammer spring.
Bill Geissele of Geissele Automatics has an interesting video on YouTube about how he started his company by designing triggers and the use of full power hammer springs. Bill was just getting started, his first trigger was the Hi-Speed National Match. While at a match and partnered up with someone from the Army Marksmanship Unit, he and his trigger caught their attention.
He was talking to the on-site commander at the AMU trailer and they were asking about his trigger. They were happy to learn that it used full power springs. The experience of the AMU, and many other military units, is that light hammer springs led to inconsistent accuracy. It usually showed up as vertical stringing of shot groups.
Wrapping Up on AR-15 Triggers
Most people are well-served by a quality mil-spec trigger like those from ALG Defense (ACT) or the BCM PNT. For individuals who prefer a two stage trigger than the LaRue Tactical MBT is hard to beat. If you’re a Geissele fan boy than the SSA or SSA-E will serve you well. But as previously mentioned it is hard to differentiate between those and the LaRue MBT.
Upgrading the fire control group should be something that a new shooter progresses to. Most shooters will be better served by learning core shooting fundamentals. Once you have achieved a proficient level of trigger control and shooting skill, then an upgraded fire control group will pay off more dividends.
As previously noted there are fire control groups available on the market that are not suitable for beginners or those without strict trigger control. When looking to upgrade, these should not be considered until you have progressed upwards from other enhanced fire control groups. I can’t tell you how many of these style of triggers that I’ve seen shooters have negligent discharges with, as well as some that have inadvertently bump fired to the point that they sound like they are a select fire weapon. Remember, you are responsible for each shot that you fire and every bullet has a lawyer attached to it.
The bottom line is you should decide what the purpose of the AR is for. Next decide what use you need your trigger to fill. Then do your homework on the options, and buy quality. However, do yourself a favor and do not use the trigger as a crutch for bad fundamentals.