ar15 "trigger job"?

[Kingcreek]

I came across this and thought I would give it a try. http://www.junkyardgenius.com/firearms/ar-15/ar08.html
It worked pretty good and the trigger stop improved the travel and feel of the trigger but now the safety doesn't work ie the hammer will drop no matter if the selector is on safe or fire. I filed the trigger part protruding into the selector hole and I must have removed too much. I assume I should I have scribed it with the hammer in the cocked position and I don't recall but I must have done it in the fire position?
I have another hammer coming but I think I'll try to get a spot of weld on the original and play with it some more.
or maybe I should toss the old trigger and set screw and forget it. I was trying to get a cheap trigger job for my varmint AR. The set screw was only 36 cents but the new hammer is costing me $14. still a pretty cheap lesson I guess.

 

[triggerman770]

ar15"Trigger Job"

If your trigger is MIM(metal injection molded) the welding may burn it down instead of building it up. If it was barstock you can give it a shot.

 

[Strykervet]

I don't know, that doesn't look like something I'd trust. If I were you, I'd scrap those parts.

I'll tell you what I did. It saved me a lot of money, as I didn't have to purchase a nice trigger, and it is also safe as long as you don't remove a lot of material. I got a parts set that included a DPMS trigger pack. Don't know which others will work, but I do know Olympic won't work. The engagement surfaces on their stuff is parkerized. You need the trigger parts that have ground engagement surfaces (like the DPMS does).

You simply take the parts, lock them down in a vice preferably, and using a very fine grit stone, kind of like a fine knife stone, you polish the ground engagement surfaces without changing the angles. Keep it flat, just remove enough to polish. When it is uniformly smooth and even, then you can use the dremel with a cotton drum to polish it further.

The trick is to just polish the trigger and hammer surfaces to the point they are uniform and smooth and shiny. A tiny bit of grease, and I got a trigger that is between 4 and 4.5lb, very smooth with a crisp release. I was going to put in an overtravel screw, but there isn't really any to speak of, it isn't worth the hassle. DPMS makes a nice trigger set, all it needed was some polishing to be a great one.

This is the trigger I use in my M4. I have another setup with a 2 stage RRA trigger. A little polishing made it nicer too. But the single stage stock one polished up is almost as good, and it really is good enough I can't justify getting a more expensive one.

 

[Red Cent]

Strykervet, you had better not let Chris Rimes know you did that .

The AR is known for its skin deep hardening. Doesn't take very much to go through. I polished with a Dremel and some liquid polish.

The really neat thing about this trigger job is that the set screw lifts up the back of the trigger group causing the hammer and sear to have an almost -0- degree (flat) interface. The factory AR trigger actually forces the hammer back more when pulling the trigger. A bunch of negative interface.

As you probably know the safety "bolt" is cut/cammed to fill the space totally when turned to safe. Nothing needs to be hardened or heat treated at that contact surface. Something fairly strong like JB WELD will refill the space and can be contured to the exact fit.

I did this mod along with the .15 cent trigger job and I have a 3# no creep, crisp trigger.

 

[Red Cent]

After typing this and considering the fix to the problem I had an epiphany. When the safety is turned to "ON", the safety bar is rotated to fill up the space between the trigger and the safety bar not allowing the trigger to move.
What if you used something like JBW to fill a little of the slot when the safety is turned to "OFF"? By taking this filler down a little at a time and testing the trigger, you would eventually achieve the trigger break and a trigger stop. Might need to go just a touch more to ensure reset.

Comments?

 

[Red Cent]

Strykervet,
Actually most "trigger jobs" include changing the angles. One case in point is the 10-22. When you pull the trigger on the 10-22 (the trigger group is out and in the hand) you can see the sear move the hammer back a little.

In this thread, the pictures show what we do if we don't buy "drop ins".

http://www.rimfirecentral.com/forums/showthread.php?t=122386&highlight=cletus+hungwell

'Course, if you create a bunch of positive interface, you gotta problem. Then new hammer and/or trigger time.

 

[Kingcreek]

Red, Thanks for sharing your epiphany. The new trigger is in and much better than the original. I am going to play with the set screw and build up the old trigger bar a little and try it again. I had the same epiphany last night but didn't have any JBW so I used some other old epoxy that I had but it didn't harden enough. oh well, cheaper than some experiments...

 

[Strykervet]

Strykervet,
Actually most "trigger jobs" include changing the angles. One case in point is the 10-22. When you pull the trigger on the 10-22 (the trigger group is out and in the hand) you can see the sear move the hammer back a little.

In this thread, the pictures show what we do if we don't buy "drop ins".

http://www.rimfirecentral.com/forums/showthread.php?t=122386&highlight=cletus+hungwell

'Course, if you create a bunch of positive interface, you gotta problem. Then new hammer and/or trigger time.

Yeah, I know that most trigger jobs involve angle changes. But what I am saying is that it is tedious and it is better to have learned this in a shop, or at least studied well on it. It can be dangerous. I've heard about bad accidents from sloppy trigger jobs.

All I'm saying is that polishing is an easy way to get a decent trigger from a stock one.

I'm also saying that you should leave angle changes to the professionals, or else REALLY KNOW what you are doing. I know enough about trigger jobs and angle changes that I know I need to know more indepth stuff. If I had a junker or two to practice on, I might, but I don't so back to the books. I don't know about you guys, perhaps you've worked on more than I have. I started out tinkering with an M4 trigger and a Glock trigger, and before I knew it, I have polished everything I own. No regrets.

I don't think my polishing job would have affected any hardening there was, but I can't tell (on the small Glock parts, I am sure I did, but those parts are cheap enough to replace if something happens). I seriously remove so little material... Once it shines, it's done. The stone just gets it started and levels the grooves and lands from the cut. At any rate, re-hardening wouldn't be impossible, we have lots of little metals shops around here. So far though, no problem.

I did a trigger job on an FAL using a similar approach, except here I changed out a few springs (not the hammer spring though) and I drilled and tapped a hole in the triggerguard for a set screw that I loctited in place for a trigger stop. I'd say I have the warhorse down to about 5lbs or so with very little overtravel. It is still a little "sticky" during travel, but that will be easy enough to fix. I wanted to see if the FAL would make a decent SDM rifle... Still waiting to see.

Just getting it this far is a huge improvement. I like a nice reliable trigger, but I like a safe trigger better.

Oh yeah, who is Chris Rimes?

 

[Red Cent]

http://www.thehighroad.org/showthread.php?t=601965&page=3

 

[Kingcreek]

I finally fixed it with some JB Weld and tweaked it until it has a nice trigger release and the safety works. I would not trust this for a serious AR where total reliability is not optional but its OK on my varmint rig.
I'm packing the new unmodified trigger and some other spare parts to go along on my prarie dog shoot. I got a nice handload worked up with 60gr V-Max bullets and A2520 powder.