KNS pins and Wilson Combat pins are viable options

Over time, the repetitive motion of trigger components can cause the pins to loosen and potentially slip out, especially if the trigger pin holes become elongated or "egged" in shape.

Trigger pins are generally steel, and AR15 lower receivers are mostly 7075 T6 aluminum.

Steel Pin Exerting Tension on Aluminum 

7075-T6 aluminum is known for its high strength and good fatigue strength, but it is softer and less durable than steel. Steel trigger pins are exerting tension on the aluminum, and over time these can happen:

Wear and Deformation: Over time, the harder steel pin can wear down the softer aluminum around the hole, leading to deformation. This is especially likely if the pin is subject to frequent or intense movement, which can accelerate the wear process.

Elongation of the Hole: The constant pivoting and tension exerted by the steel pin can cause the aluminum hole to elongate or become "egged," altering its original shape. This is due to the aluminum's lower hardness and strength compared to steel, making it more susceptible to deformation under stress.

Increased Friction: As the aluminum hole deforms, it can lead to increased friction between the pin and the hole. This can further exacerbate wear and may require more force for the pin to pivot, potentially affecting the performance of the mechanism that relies on this pivot action.

Galling: Galling is a form of wear caused by adhesion between sliding surfaces. Since steel and aluminum are dissimilar metals, the friction and movement can lead to small particles being torn off and welded together, causing further damage and possibly seizing the pin in place.

Drop In Trigger

For drop-in triggers including single and 2 stage triggers, designers have optimized performance by housing them within a self-contained unit, ensuring precise pin installation. This approach addresses the variability in AR15 lower receivers, where hole tolerances can differ slightly between brands. 

Since trigger manufacturers cannot control these variances yet still aim to deliver consistent performance as intended, the solution is to encase the triggers in a module. This self-contained unit can then be easily inserted into any lower receiver, bypassing potential inconsistencies in the lowers' specifications.

Now imagine if out of spec trigger pins distance (without anti walk pins) can affect trigger pull. Yes it could slightly change how much contact surface there is.

The primary distinction between a semi-auto and full-auto trigger lies in the mechanism that determines how many rounds are fired with a single pull of the trigger. In semi-auto mode, one pull results in one shot, while in full-auto mode, the firearm will continue to fire as long as the trigger is held down.

AR15 Trigger Parts

Trigger: This is the "go" button. When you pull it, the rifle releases the hammer, which, if a round is chambered, will fire the weapon.

Hammer: This is a large, flat-faced piece of steel at the top of the trigger assembly. It rotates up and down, and its face strikes the firing pin inside the bolt carrier group, igniting the primer on a chambered round.

Sear: Located at the front of the trigger, the sear keeps the hammer cocked until the trigger is pulled. A cut-out on the bottom of the hammer engages the sear while at rest. Pulling the trigger angles the sear downward, releasing the hammer to strike the firing pin.

Disconnector: After firing a round, the bolt carrier group (BCG) is pushed back into the buffer tube by the gas system. As the BCG moves backward, it pushes the hammer back down into the trigger assembly. The sear usually holds the hammer down when cocked, but since the trigger was pulled to fire a round, the spring-loaded disconnector catches the hammer to prevent it from flying back up.

Hook: When the BCG forces the hammer down, a hook on the back of the hammer temporarily catches the disconnector. As you release the trigger, the sear moves back up to cock the hammer. The disconnector then slides off the hook, allowing the hammer to be held by the sear and cocked. The trigger resets, and the firearm is ready to fire again.

Check out this video showing how the trigger works

AR15 Trigger Spring

Why are mil spec triggers so heavy? About 6 to 10 lbs. While this is fine for military applications and safety, it's not great for those looking to make precision shots at long distances or rapid fire in competitions.

Part of the reasons is because the parts are not polished and the trigger spring isn't optimized. So you need a lighter trigger spring. 

These are available to buy, and most aftermarket AR15 triggers have it included.  These upgrades improve the trigger pull weight by eliminating any rough or jerky trigger feel.

AR15 Trigger Pin Size

Most AR15 on the market right now are all 0.154" diameter pin hole size. They are often referred as "small" pin hole size. Most AR15 trigger upgrades will label them as either "small" or "large". Most are small.

Large size pin hole 0.170" is mostly older semi auto Colt AR15 lower receivers back in the day.

AR15 Trigger Performance Terminology

Take-up: This is the loose feeling you get when you first pull a trigger. It's like squeezing the trigger without anything happening right away.

The wall: After any loose feeling, you'll reach a point where the trigger feels tight. This is "the wall." It's where the trigger starts to really work.

Creep: This is the trigger moving just before the gun fires. Some people don't like creep, but if it's smooth, it can help you shoot better. If the creep feels jerky, we call that "trigger stacking."

Stacking: This is when the trigger feels stuck and you have to push harder to make it move. It's not good because it makes the trigger unpredictable.

Pre-travel: This is everything that happens before the gun fires. It includes take-up, the wall, and creep.

Trigger break: This is the moment the gun fires.

Over-travel: This is how much the trigger moves after the gun fires. If there's a lot of over-travel, it takes longer for the trigger to be ready again.

Single Stage VS Two Stage Trigger

A single stage trigger is designed for rapid shooting, where the shooter feels the trigger wall instantly without any take-up, and the trigger breaks immediately. This design is ideal for competition and defensive shooting, offering a trigger pull weight typically between 3.5 to 5 lbs.

On the other hand, a two-stage trigger is tailored for precision shooting. 

It features an initial take-up as the first stage, followed by a super light second stage trigger pull. This design ensures the lightest trigger pull without causing finger tremors, especially during long-range shots. The first stage acts almost like a preparatory phase, getting the shooter ready for the second stage.

While both designs have their merits, the choice boils down to personal preference and the specific shooting scenario. check out the comprehensive guide on single vs two stage trigger to learn more

The main things to improve is to remove the gritty trigger feel, that friction, and a fair amount of creep.

There are many replacement triggers available. Many single stage or two stage triggers can greatly improve your rifle's trigger performance immediately. Most of these triggers cost between $100 and $300.

Getting a gunsmith to fix the trigger can cost the same. But doing a basic trigger job on your own is a cheap way to make your rifle work better. You can even do it for $30 or less.

Step By Step AR15 Trigger Jobs

Let's understand what a AR15 trigger job is. Sometimes, the standard trigger feels rough and hard to pull. This roughness is because of the trigger's rough surfaces and the tightness of the springs. To make the trigger smoother, we'll polish these surfaces on the trigger, hammer, and disconnector.

Upgrading The Trigger Spring

To change the pull strength, we'll MUST put in a new set of springs for the hammer, trigger, and disconnector. There is no way to modify existing trigger spring's pull strength by DIY method.

JP reduced power spring kit works well, and that reduces the trigger pull down to 3 to 3.5 lbs. However the exact trigger pull weight will differ a little from each trigger job project.

Polishing The Trigger Components

When you polish the touching parts, it's important to keep their shapes the same. If a part is flat, keep it flat. If it's curved, make sure it stays curved and don't change its shape. 

Do not use a dremel to do this because the amount of material to polish is very little, a dremel tool will generally remove too much and damage the part completely due to the uneven grinding wheel surface.

Use a high 3000 to 8000 grit whetstone to polish. Start with 3000 at the start and end with 8000 grit. Wet the whetstone as the instructions say. Once it's ready, place it on a surface that doesn't slide to make sure it stays flat while polishing.

After polishing both parts until they shine like a mirror using high 8000 grit, you're done with the trigger polish.

Polishing The Hammer

For the hammer, there are two parts to polish. Start with the little edge on the hammer. This little area interacts with the trigger that we just polished.

This type of AR15 trigger tuning is so easy that anyone can do.

Polish The Disconnector

The final step is to shine up the hook on the disconnector. The disconnector catches the hammer, and it is responsible for resetting the trigger. The length of the contact between the disconnector and the hammer determines how much trigger has to travel when resetting.

For the context of this guide, let's keep it where it is.  

Usually, this part is flat. But sometimes, based on who made your disconnector, it might have a small curve. If it does, keep that shape using a round file covered in high grit sandpaper, which you can get at car part shops.

If it's flat, polish it like you did the flat side of the hammer. Start with 3000 grit and go up to 6000 grit until it shines like a mirror

Put Everything Back

Lastly, put everything back including the new trigger spring kit. Test the trigger and ensure its functionality. When dry firing the trigger inside the lower receiver, make sure the hammer isn't pounding on the bolt catch, please use a hammer drop block.

Normally, the hammer will hit the firing pin with the upper receiver installed. Without the upper, the hammer just hits the bolt catch.

Buying Aftermarket Trigger

If you want to skip all these DIY stuff and just buy something that's engineered to perform well like the Geissele or Timney triggers, please check out this page where the best are recommended.

Once the shooter pulls the trigger and the gun fires, the bolt carrier's rearward motion resets the trigger. This mechanism pushes the trigger back to the shooter's finger, readying it for another immediate shot.

By doing so, the FRT allows for a more rapid rate of fire without technically making the firearm fully automatic. However the perceived high rate of fire has the ATF worried even though it falls under the physical definition of semi auto.

Who Makes Forced Reset Trigger

The two most popular ones are WOT and Rare Breed.

Is It Different Than A Binary Trigger

Binary triggers don't turn AR15's into machine guns, so laws like the Gun Control Act and National Firearms Act don't regulate them. A forced reset trigger is not the same as a binary trigger based on its physical operational characteristics.

A binary trigger is a special type of firearm trigger designed to fire one round when pulled and another round when released. So, for each complete trigger cycle (pull and release), you get two shots fired. The process goes like this: when you pull the trigger, it fires a shot (Pull - Bang). Then, when you release the trigger, it fires another shot (Release - Bang). Only after that does the trigger reset for the next action. Binary triggers typically have a 3-position safety lever: safe, semi, and binary.

A forced reset trigger, on the other hand, does not fire a round upon release. Instead, after the initial shot is fired on the pull, the trigger is automatically "forced" back into the reset position by the firearm's mechanics. This allows the shooter to fire again more quickly than with a traditional trigger because they don't have to manually release the trigger for it to reset. The emphasis with a forced reset trigger is on rapid semi-automatic fire, whereas the binary trigger's distinction is firing on both the pull and release actions.

Are Forced Reset Trigger Safe?

The forced reset trigger is new on the market, so we don't have enough data about its safety. Beginners should use a traditional trigger with a clear pull and reset.

This way, they won't be caught off guard by the different feel of the forced reset trigger and mistakenly fire extra rounds.

What's The Current Legal Status On Forced Reset Trigger

Based on one APnews report, In court filings, the ATF said testing on the FRT-15 triggers showed their rate of fire can meet or exceed that the military's M-16 machine gun, which can fire 700 to 970 rounds a minute. Read more here

Some US judge calls ban on forced reset triggers for guns "likely unlawful", while others call the opposite. 

Based on the ongoing legal battle to determine whether forced reset trigger is legal under the definition of the ATF, we do not recommend viewers of this content to purchase one. There are plenty of great triggers for AR15 that provides competition level speed and reliability without the legal worry. Check them out here

It's like the door hinge concept. It's harder to push a door open closer to the hinge than further out.

Enhanced leverage: The flat trigger bow allows you to slide your finger farther down, closer to the end of the trigger. It's almost like applying slightly more torque when the finger tip is at the end of the trigger bow bar.

• This positioning provides increased leverage, resulting in a lighter feeling trigger pull.
• Flat trigger forces the trigger finger not wrap around the trigger bow too deep (Typically with curved trigger bow)
• The additional leverage can be beneficial for making accurate shots, particularly when precision is crucial.
• Works for both single stage and two stage trigger systems

Clear trigger reference point: With a flat trigger, there is usually a slight bump on the end, serving as a reference point for your finger placement.

This feature allows you to have a consistent grip and a reliable sense of where the end of the trigger is located, facilitating more consistent shooting.

Note: This doesn't mean the shooter with no experience will suddenly improve when using a flat face trigger. Experienced shooter who prefer curved trigger bow can shoot just as well as what flat trigger bow is designed to do.

Trigger finger is only a small part of the overall shooting mechanics. The grip placement, shoulder muscle, hand muscles tension, support hand placement and posture can all affect the shot.

Check out recommended AR15 trigger upgrades

Curved Trigger Bow

Comfortable finger placement: Some shooters prefer the ergonomics of a curved trigger bow. The curve naturally accommodates the shape of the finger, allowing for a comfortable and secure placement.

This can be advantageous when shooting for extended periods or with gloves.

Versatility for different finger positions: With a curved trigger bow, shooters have the flexibility to place their finger at different positions along the curve, depending on personal preference or shooting technique.

It works for both single stage and two stage trigger systems.

This adaptability can provide a customized feel and may suit individual preferences.

Single stage is designed for fast split time shooting. Typically 3.5 to 5 lbs trigger pull weight for competition shooting as well as defensive shooting. The shooter senses the trigger wall immediately without any trigger take up, and the trigger breaks. The trigger then resets with minimum travel and it's at the wall again. 

Single stage trigger can also feature flat face and curved trigger bow

Geissele Super Dynamic Flat Trigger

This subtle feature significantly reduces trigger split time for competition shooting.

Two Stage - For Precision Shooting

Two stage trigger is good for precision shooting as well as defensive shooting. It features a small take up to prepare the trigger as the first stage trigger pull ( 2 - 2.5 lbs), and the super light second stage trigger pull follows after (about 1.5 lbs on average).

American Gold 2 Stage Trigger

The reason for this design is to have the lightest trigger pull without introducing finger tremor for long range shots, and the first stage acts almost like a safety stage to at least get the shooter ready at the second stage wall.

Two-stage triggers that are commonly issued in the military (About 8 lbs trigger pull weight) but many professionals preference for aftermarket single-stage triggers. Not all two-stage triggers are equal in terms of quality and reliability. 

Please check out MBT (Meticulously Built Trigger) as a reliable two-stage trigger option

Does It Really Matter

Yes, the shooting experience is significantly different once you get some range time with them. For the most part, these trigger systems provide much lighter trigger pull weight and much crispier trigger break. Whether you are shooting with gloves on or off, in the freezing cold or 

For experienced shooters who understand the mechanics behind these trigger systems will appreciate both designs. Most aftermarket single stage and two stage triggers both feature reduced trigger pull weight in the range of 3.5 to 5.5 lbs.

While a standard mil-spec AR-15 trigger costs almost nothing to make, and the trigger pull weight is about 8 - 9 lbs.

However, if the trigger weight is too light, it can be a safety concern. In addition, if the trigger runs faster than the bolt can complete the full cycle, then the rifle can expect light primer strike when the hammer is riding the bolt as it returns to chamber a new round.

Trigger pull weight is a critical factor that affects various aspects of shooting performance with your AR-15. Let's explore the key considerations when determining the ideal pull weight for your rifle:

Accuracy

A lighter trigger pull weight can contribute to improved accuracy as it minimizes the finger muscle effort required to release the hammer. By reducing the finger tension needed to fire, shooters can maintain better control and focus on precise shot placement.

Speed

For those seeking to enhance their shooting speed, lighter trigger pull weights provide a distinct advantage. With less resistance during trigger pull, shooters can achieve faster follow-up shots, significantly reducing the time between rounds.

Check out some of the best AR15 triggers here

Discharge Safety

It is crucial to exercise caution with lighter trigger pull weights, as they may increase the risk of accidental discharges if not handled properly.

The sensitivity of lighter triggers can make unintentional follow-up shots more likely, especially when the rifle recoils and inadvertently impacts the shooter's finger.

Compatibility

Certain AR-15 triggers with lighter pull weights may feature smaller springs, which can pose compatibility challenges when using ammunition with hard primers.

This consideration is particularly relevant for shooters utilizing steel-cased ammunition, where a heavier trigger may be preferred to ensure reliable ignition.

Recommended Trigger Pull Weight Ranges for Common Applications

To optimize your AR-15's performance, it is important to select the appropriate pull weight range based on your specific application. Here are the recommended pull weight ranges for common uses:

Home Defense Pull Weight: 5 to 7 pounds

When it comes to defending your home, certainty and control over each shot are paramount. Choosing a heavier trigger with a pull weight between 5 and 7 pounds promotes deliberate trigger pulls, reducing the likelihood of accidental discharges.

Additionally, medium-weight triggers in this range won't compromise accuracy when engaging targets at self-defense distances.

Competition Shooting Pull Weight: 3 to 5 pounds

In competitive shooting scenarios, speed and accuracy are of utmost importance. Most competition shooters prefer triggers with a light pull weight, ranging from 3 to 5 pounds.

These triggers facilitate rapid and precise shot placement, allowing competitors to excel while completing courses within the shortest possible time.

Trigger Type and Its Influence on Pull Weight

The type of trigger installed in your AR-15 can significantly impact the optimal pull weight selection. Let's explore how different trigger types affect the ideal pull weight:

Pull Weight for Single-Stage Triggers

Single-stage triggers release the hammer as soon as the shooter applies sufficient pressure, without any slack or additional stages. Shooters using a single-stage match trigger often opt for the lightest pull weight possible.

However, for home defense firearms typically feature single-stage triggers with pull weights between 5 and 7 pounds, ensuring a deliberate and controlled trigger pull.

Pull Weight for Two-Stage Triggers

In contrast to single-stage triggers, two-stage triggers operate in two distinct stages. Upon pulling the trigger, a "break wall" is encountered, providing a stopping point between the first and second stages. This design allows shooters to align their shots and prepare before firing.

Custom two-stage triggers offer the advantage of setting different pull weights for each stage. For example, you can configure a trigger with a 3-pound pull weight in the first stage and 1 pound in the second stage, granting maximum control over shot execution and enabling precise trigger manipulation.