To make your AR rifle feel and work better, upgrade to an fine tuned aftermarket AR15 trigger group. However, the regular AR trigger works and they can be improved, but it can feel rough and heavy when you first get it.
Only try this if you really know how the AR-15 works and have the right gunsmithing skills. Anything you do to your rifle is your own responsibility. Accidently filing off too much material on critical spots of the trigger component can lead to rifle malfunction. Always test before loading live ammo.
What Is There To Polish?
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 Job
Let's understand what a trigger job is for an AR-15. 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.
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.