Understanding The AR Trigger

It’s common knowledge that the most effective upgrade to the AR-style rifle is a trigger upgrade. But have you ever wondered why?
Understanding The AR Trigger

AR sales are still very strong, but there’s a lot of money to be made in upgrading the rifles that have already been sold. The best and easiest upgrade in my mind that any retail shop can do is to install a new trigger, which comes with a huge number of options and choices for the customer. Indeed, new trigger groups have been custom designed for tactical users, long-range shooters as well as competition shooters. And each has something unique to offer, and an upgraded trigger is an improvement that customers can see and feel immediately.

The AR-style rifle was designed with a single-stage trigger, and the vast majority of both commercial and Mil-Spec ARs will come standard this way. Mil-Spec triggers can have a pull weight that varies from 5½ to 8½ pounds. Typically, too many Mil-Spec triggers also have a gritty feel that makes it hard to tell when the trigger will break. A mediocre trigger can lead to poor trigger mechanics, bad habits and missed shots. People who have used only Mil-Spec triggers don’t know what they’re missing so to really make the sale you have to let people try what a custom trigger feels like.

Retailers should also be wary of, or perhaps grateful for, the home gunsmith. Yes, it is possible to improve the Mil-Spec AR trigger by smoothing the contact surfaces, but it is not a good idea. Standard AR triggers have a surface hardening treatment and unless someone is a very knowledgeable gunsmith with the right tools, there is a real risk of removing this hardening and significantly shortening the life of the trigger.

The best option is to replace the entire trigger with a quality after-market single- or two-stage trigger group.

Single-Stage vs. Two-Stage Triggers

In a standard two-stage trigger, which was common in U.S. military rifles before the M-16, the shooter will first encounter take-up, which is the distance the trigger travels with very light pressure before it starts to engage the sear and more pressure is needed. At this point the trigger is under only light spring pressure. When there is no spring pressure at all it is referred to as slack.

Creep or travel is the distance the trigger moves under tension after the take-up or slack is gone and before the trigger breaks and the gun fires. You don’t want too much creep but none is unsafe. You also don’t want any stacking, which is when the trigger weight increases during travel. After the gun fires you may experience overtravel, which is the distance that the trigger continues to move back after the gun fires. This can cause the shooter to overcompensate for the trigger squeeze and pull the gun off target.

On a single-stage trigger, there is no take-up or slack and the trigger is engaging the sear as soon as the trigger squeeze starts. A bad AR trigger with lots of creep can make a single-stage trigger feel almost like a two-stage trigger. Also, neither single-stage nor two-stage trigger systems effect the actual weight of the trigger or how much pressure is required on the trigger to fire the gun, but it can affect the perceived weight. The more pressure is required, the heavier the trigger, the harder it can become to shoot accurately, but too light a trigger can be unsafe particularly in high-stress tactical situations.

Many competitive shooters, especially those who got used to older model military rifles, will prefer a two-stage trigger because it allows the shooter to prep the trigger like on a Glock, for example. But since too much take-up can be a distraction, other shooters prefer single-stage triggers, which is the way the AR was originally designed to function. Regardless, all triggers should break clean or with no stacking or overtravel and it should feel smooth and even, not gritty.

Tactical Retailer spoke with David Clark of Trident Trigger, a manufacturer of AR trigger groups, about the elements of a quality trigger:

“First you want to minimize all creep, the distance you have to pull to have the trigger break. You want a trigger break that feels clean and crisp with no grit,” he said. “Some manufacturers will use lighter springs and hammers to reduce pull weight, however this also produces lighter firing pin strikes on the primer which can affect reliability especially in .308 and 7.62x39-chambered rifles or when using harder military primers in 5.56. Competition and 3-gun shooters value a distinct tactile and audible reset.

“I do want to mention that some of the large retailers we have been supplying to recently have mentioned that the matter of reliability is becoming a factor in trigger sales. A purchasing agent told me that of the triggers they carry, several are known for light primer strikes and on a few they cannot get through a 30-round magazine without light primer strikes. I mention this because reliability might be a weighted concern just as valid as pull weight.”

Drop-In vs. Standard-Trigger Groups

Replacement trigger kits are available in two basic varieties and manufacturers tend to only make one or the other. In the standard trigger kit, the springs, trigger, hammer and disconnector are all separate (just like on a Mil-Spec rifle). These have to be assembled and installed which is a fairly easy process. “Drop-in” trigger groups come entirely self-contained inside a casing and all the trigger parts are pre-assembled. For these all you have to do is remove the trigger and hammer pins, remove the old trigger parts, drop in the casing and replace the pins.

Some people prefer the drop-in trigger because they are marginally easier to install, but some prefer the standard trigger kits because they think the drop-in triggers are harder to clean or maintain. And it is true you have to replace the entire drop-in trigger if one part breaks and that they are harder to keep clean.

Also, anyone who owns a Colt AR should be aware of what size hammer and trigger pins are used. Colt ARs were made for a time to be non-Mil-Spec so upper and lower receivers as well and new trigger parts will not fit without the proper-sized pins. Many trigger-group manufacturers will offer both versions.

The installation procedure for all the triggers listed is fairly similar and each includes instructions with several manufacturers featuring online videos as well. All that is needed is a set of hammer and punch.

Start by ensuring that the rifle is unloaded then separate the upper and lower receivers, set the safety selector to the fire position and squeeze the trigger riding the hammer forward. Do not let the hammer slam against the rear of the magazine well.

It is not necessary to remove the safety selector to remove the trigger parts, but it does help and some manufacturers require that the safety selector be removed in order to install their trigger systems.

To remove the safety selector, first remove the pistol grip carefully to not lose the safety detent, which may come out, and the detent spring, which will definitely come out. Using a punch and hammer, drive out the trigger and hammer pins and remove while holding them from the top because they are under spring tension.

Next, install the trigger and the trigger pin — some kits use the old pins and some include replacement pins. Install the hammer and hammer pins and reinstall the safety selector, detent and detent spring and pistol grip. While most kits ask the installer to remove the pistol grip and safety selector it is thankfully not necessary on the vast majority of drop-in trigger systems, which vastly speeds up the installation to 5 minutes or less.

Trigger Pull Weights

Trigger kits from different manufacturers are available with different or occasionally adjustable pull weights as well as differently shaped triggers. According to Clark, selecting between a straight or more traditionally curved trigger is a matter of personal preference.

“We find that the newer military shooters prefer the flat, but most seem to like the the feel of the other,” he said. “We sell 4:1 curved over flat. Curved triggers are easier for the finger to index to the same spot and ergonomically correct for the finger pad. The flat triggers look cooler to many people but they tend to have a lower pull weight at the bottom than at the middle since it is a lever.”

While all after-market trigger kits should exhibit excellent dynamics and feel, they are nonetheless available in a variety of weights. Tactical users, especially any law enforcement customers who face significant scrutiny, are better served with a heavier trigger.

A heavier trigger is also better suited for gloved use where there is less tactile sensation. In this category 4½- to 6½-pound triggers seem to be appropriate, with the lower weight being the most popular. Those users who are more heavily focused on making precision or longer-range shots are going to prefer lighter triggers and even two-stage triggers.

We again asked Clark how his sales stack up and what customers seem to prefer.

“Our sales are pretty evenly divided between 3- and 4-pound trigger kits,” he said. “A good rule of thumb of advising customers is to ask how they are running their rifle. If you run iron sights, go with the 4-pound trigger; if you run a scope, go with the 3-pound trigger. This seems to work well for most people.”

A great way to close a sale on an upgraded trigger is to allow customers to try a standard trigger next to one of the custom after-market trigger groups. This can be done by having an upgraded trigger installed on a display rifle or with a trigger housing unit that allows the customer to pull the trigger and see the internal mechanics at the same time.

Many manufacturers can provide this to retailers, but only one come standard this way. The new Ruger Elite 452 AR-Trigger comes packaged in its own polymer AR housing complete with ergonomic pistol grip, thumb safety and triggerguard. The customer here gets the added benefit of all the extras Ruger offers and can get a real feel for the trigger.

There are a lot of accessories that customers buy because they look cool. In the case of an after-market trigger, your customers will feel cool and shoot better, which encourages people to shoot more often and even helps drive ammunition sales.

If you combine your sales with any sort of training you can also use target diagnostics to recommend an improved and lighter trigger to help customers improve the groups sizes.

Over the years we have tested a lot of AR rifles from a dozen manufacturers and almost every single one benefited substantially from a new trigger group. This not only made shooting more enjoyable but also produced a significant improvement in group sizes. Your customers will be thanking you for this one.


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