Improving trigger pulls usually works as one of, or a combination of three methods:
- Reducing friction between parts where they interact, usually by polishing
- Reducing spring tension, so there is less pressure to overcome for the parts to function
- Changing the geometry of parts and/or surfaces so there is less metal to metal contact. Less contact means less friction.
Following the instructions below, you should be able to make the trigger pull both smoother and a little lighter. When you reassemble the hammer and trigger make sure the hammer legs are resting on top of the trigger pin and not underneath it. A little Moly Slide paste on the sear surfaces will make the trigger pull even slicker. Once it’s back together, perform a function test to make sure the safety and all the other parts are working properly.
Steps for Improving Tripper Pulls:
- MAKE SURE YOUR GUN IS UNLOADED. You’ll need to separate your upper and lower receivers. To do this simply push the forward and rear take-down pins out, left to right. Next, hold your thumb on the hammer. Keep pressure on it, and pull the trigger to de-cock it. Let your thumb control the hammer as it rides forward to its un-tensioned state. Don’t just let it smack forward; it can bang up your receiver and possibly crack it.
Here you can see the hammer fully forward:
- Carefully study the pictures below and note the orientation of the springs, etc. The hammer springs must sit ABOVE the trigger pivot pin when re-assembling the parts: this is pretty important.
- There’s no need to remove the spring; it will move around and you can get it out of the way as you work. Keep it on it can get twisted and messed up during removal. It won’t hurt anything keeping it on. Next, we want to drift out the trigger pivot pin.
- Points A and B are the ones that we’re mostly concerned about, as these are the contact points when the trigger is fired most of the time. If these two points are polished up, is will smooth that famous gritty AR-15 trigger substantially. Points C and D are where the disconnector interfaces with the hammer and it affects trigger pull off the reset. If you decide to polish those do so very gently. A little is a lot on those areas.
- Polish both sides of that square lug in the front of it. We’ll use the 600 grit for this initially. As they come from the factory, most AR-15 triggers have very roughly machined surfaces. You can see that here, in the silver area in the front of the trigger. What we’re aiming to do is to remove those machining marks, yet keep all these surfaces square and true. Any rounded edges, burrs, and “oops”es can ruin a trigger pull faster than you can blink. The squarer and sharper you can keep the edge of that lug, the crisper your pull will be.
- For the hammer. The little sear notch in the back of the hammer is where that square lug on the trigger interfaces. Wrap the sandpaper on a thin nail file and gently work the bottom of the notch. This is the hardest part to get right and the easiest to screw up, so I’d like to tell you to just gently polish the area with a few strokes of 600 and then 1000 grit paper. If you take too much metal off, the trigger may not catch and the gun won’t work.
- Polishing those two areas, should make a world of difference in your trigger pull, just reducing the grittiness of the pull. It won’t make it actually lighter, but it will give you the illusion of a lighter pull through smoother trigger/hammer interaction.
- Lightly grease all the points I just polished before re-assembly; this will help the parts slide apart better. Then the trigger goes back in the gun. Work it back into the receiver, and push it down through the hole in the lower receiver. To keep it in place while you work on it, push one of the pivot pins in just far enough to hold it, but not so far that it will keep you from getting the disconnector back in. Then push the disconnector down against the small round spring’s tension, until the hole lines up with the pivot pin hole in the trigger. Gently tap the trigger pivot pin through. Using the punch through the opposite side of the receiver can help you line things up as you push the pin through.
- Note the orientation of the spring on the hammer. This is critical if you want your gun to work properly. Now, lay those two legs of the spring down on top of the trigger pivot pin. And push the hammer downwards, against the spring tension, until it aligns with the holes in the receiver for the pin. Push the pin through and keep wiggling the trigger until the pin is aligned and properly through the other side. They should fit flush.
- Re-assemble the upper receiver on the lower, and try it out. Dry firing the gun is fine (MAKE SURE IT’S UNLOADED!!!) for testing. Hopefully everything went according to plan and the pull has been moderately improved. Always take it to the range and test-fire it under safe conditions to make sure it works well, and safely.
- The basic premise of this (polishing moving/interacting parts) will work on many guns if you’re careful. Enjoy your new trigger pull, and as always, Stay safe!
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