AR15 Trigger-nometry: Instant Accuracy Boost

Estimated reading time: 11 minutes

Do you want an immediate accuracy boost for your AR15? There are two quick hacks to wring out more accuracy from your AR. One is to mount an optic. The second is to replace your AR trigger. In my opinion, the trigger is the thing. Light pull weight, crisp break, short reset, and consistency. A consistent trigger means you know when the trigger will break so you can manipulate the rifle better, which leads to better accuracy. I can live with a pistol grip or stock that doesn’t fit me so well, but gritty triggers with heavy pulls are just plain annoying. You might even be able to live with that A2-style pistol grip and stock after you experience a better trigger.

Types Of AR15 Triggers: Mil-Spec And Drop-In

Swapping out the trigger in an AR15 is an easy DIY project that even a gunsmith monkey like me can do quickly. There are bucketloads of aftermarket AR15 triggers to choose from, but there are essentially two types: mil-spec triggers and drop-in triggers. Mil-spec triggers were designed for reliability and safety in military gun, and are made up of eight parts: the trigger, trigger spring, trigger pin, hammer, hammer spring, hammer pin, disconnector, and disconnector spring.

A mil-spec trigger typically has a pull weight that ranges from 5.5 to 9.5 pounds. It’s a one-size-fits-all type of trigger that is good enough for government work as they say. Some mil-spec style aftermarket triggers, however, enhance the mil-spec design will micro-polished contact surfaces and low friction coatings like nickel teflon and nickel boron coatings for a crisp break. Some also juice up the springs for faster lock time, short over-travel, and more positive reset that you can feel and hear. Some use retainer pins so the trigger and hammer pin don’t walk out of the lower receiver under heavy use. These triggers take a bit more gunsmithing skill to install. You need to pay attention that you orient the springs correctly. 

Drop-in triggers are one piece plus two pins. They are simple and easy to install. Chip McCormick designed and patented a drop-in trigger in 2002. A drop-in trigger is the no-fuss solution to a more accurate AR15. If you can field strip an AR15, you can install a drop-in trigger; just place the unit in the lower and replace the hammer and trigger pins. That fast. That easy. 

Two-Stage Vs. Single-Stage

A single-stage trigger has one consistent pull weight from start to break. Nearly every mil-spec trigger is a single-stage trigger. A two-stage trigger has two distinct stages through the pull. The first stage is the take-up and the second stage is the wall. The choice of which type of trigger you want is personal. Single-stage triggers are the most used in AR applications. The benefit of a two-stage trigger is you can prep the trigger or press the trigger until you hit the wall. This is useful in high-stress situations like home defense or hunting. Some long-range precision shooters like two-stage triggers because they like taking up the slack in the trigger and hitting the wall knowing the shot is ready to break.

Face Types: Curved Vs Flat

Again, whether you opt for a flat trigger or a curved trigger depends on preference, but there are some benefits to both types. A flat trigger has a greater surface area for finger placement, a longer reach, and the pull weight feels lighter to many shooters. A curved trigger has a shorter trigger reach. Many shooters feel a curved trigger is more comfortable to use, and the pad of your finger settles naturally in the curve of the trigger.

AR15 Trigger Install Tools

The only tools you will need to swap out an AR trigger are a punch and hammer. Depending on your lower receiver, you may need a screwdriver or an appropriate tool to partially remove the pistol grip. A bench vise and a lower receiver vise block make it easier to work on the lower and orient it in the correct position for installation. Or you can use your kitchen table. Whatever type of trigger you decide to install, follow the manufacturer’s instructions and wear eye protection. We don’t want you poking out your eye. After verifying the weapon is unloaded, the steps are simple. 

AR15 Drop-In Trigger Install Steps 

Remove the upper receiver from the lower receiver and de-cock the hammer. Make sure you control the forward movement of the hammer; do not allow it to strike the front of the receiver. Use a punch and hammer to drift out the hammer pin.

This allows you to remove the hammer and hammer spring. Push down on the disconnector and use the punch to push out the trigger pin, then pull the trigger, sear, and trigger spring from the receiver.

Loosen the pistol grip screw inside the grip. No need to take the grip off, just allow the spring located on the right top edge of the grip and the detent pin to release spring tension on the safety selector.

Slide the safety out of the receiver. Cock the hammer on the drop-in trigger and be sure you don’t accidentally press the trigger. Place the drop-in trigger into the lower.

and press down on the trigger to align the holes in the drop-in trigger and the holes in the lower.

Insert the two pins; one for the trigger and one for the hammer. Some drop-in AR15 triggers have anti-walk pins and screws. These keep the trigger and hammer pins from rattling loose during loose. Screws secure the anti-walk pins in the lower. Replace the safety selector and make sure it is properly oriented. Tighten up the grip screw. Done.

Is Swapping Out An AR15 Trigger Worth It?

Changing stocks, rails, and pistols grips can help increase accuracy by making the rifle more comfortable to shoot, but the trigger is the best upgrade you can do for your AR15.

6 Best Mil-Spec and Drop-In AR15 Triggers

What’s the best AR15 aftermarket trigger? I haven’t used them all, but I have few choices below that I have used. Let me know what triggers you like.

Best Inexpensive AR15 Mil-Spec Trigger: BCM PNT Trigger

Forget mil-spec, BCM’s PNT trigger surpasses mil-spec standards and does it for less than $70. PNT stands for Polished, Nickel, Teflon. The parts are investment castings that are polished then given an electroless nickel finish and imbedded with teflon particles to reduce friction so there is less creep and gritty feeling. Pull weight is 4.5 pounds.

HyperFire Enhanced Duty Designated Marksman

The trigger shape of the Hyperfire Enhanced Duty Designated Marksman Trigger single-stage trigger has a duplex trigger face that is a bit curved and a bit flat. This allows you to place your trigger finger high or low on the trigger surface. The idea is you run the trigger high in tactical situations and low for more precision shooting. The trigger comes with two hammer springs so pull weight can be adjusted to 5.5 pounds with the red hammer spring or 4.5 pounds with the green hammer spring installed. This trigger will set you back about $100.

Geissele Super Semi-Automatic Enhanced (SSA-E) Trigger

You can’t talk about AR15 triggers without mentioning Geissele. The Geissele SSA-E trigger is the semi-auto version of the full auto trigger used by some US Special Ops guys. This is a two-stage trigger; first stage is 2 to 2.5 pounds, second stage is 0.9 to 1.3 pounds. It has a smooth, light first stage take-up and a crisp, candy cane-like second stage break—that’s Geissele’s description—and it’s appropriate. Ho-ho-ho. I like it a lot. It does give me sticker shock at $245.00. Is it worth it? Yep.

Best All Around AR15 Drop-In Trigger: Black Rain Ordnance DIT 3.5 LB Trigger

The DIT stands for Drop-In Trigger, which refers to the ease of installing this sweet single-stage trigger. The 3.5 stands for the 3.5-pound pull weight. The Black Rain DIT 3.5 trigger comes with KNS anti-rotation pins so extensive range time won’t rattle the pins loose. This is a dependable trigger that will cost you about $235.

Two-Stage Trigger With Low Pull Weight

Timney triggers are a benchmark in aftermarket triggers and the Timney Targa Short Two-Stage trigger is tuned for a short first stage set at 2 pounds with a 2-pound second stage. This is a very crisp, no-creep trigger that allows you to shoot fast. It is available in straight or curved trigger shoe. I have the curved face model. It will set you back $242, but it is so worth it if you want a two-stage trigger.

READ MORE: What’s A .223 Wylde Chamber? 

Best Budget AR15 Drop-In Trigger With Flat Face: CMC AR15/10 Single Stage Trigger – Flat

The CMC Single Stage Trigger features a flat trigger shoe and is available in 3.5, 4.5, 5.5, and 6.5-pound weights. The CMC Triggers is ultra crisp with no creep prior to trigger break. I use a 3.5-pound model in my AR setup for deer hunting. At $189 it is still pricey but more in line with my frugal budget. 

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