I recently had a problem with New Bushmaster Internals being too tight a fit in a new PWA lower (Trigger and Hammer)

This is what I did.

1. Got some 400 and 600 grit sand paper and wrapped it around a knife for a flat surface.

2. Sanded the sides of the trigger and hammer with it and finishing with the 600 grit ensuring it was flat and smooth.  Now it fits in nicely with no play on the sides.

3. Took my dremel with a "fabric" attachment and added some chrome pipe polisher that I use on my Harley and polished the sides to a "mirror" finish.

4. I also made sure to "round" off any "hard" corners just a little. Surface is still flat.

5. While I was at it I gave myself a "trigger job".

a. "Rounded (slightly)" off the hard corner and polished the hammer catch on the front top of the trigger mechanism.

b. Increased slightly the angle of the catch in the hammer, while "rounding" off (slightly) the hard corners, finishing off with polishing.

Gave the entire weapon a functions check and everything works very smoothly after final assembly.

Trigger is now a lot smoother and does not require the same amount of pressure to engage.  It is light and crisp, but not too light. Everything works as per functions check.  

I did find however that when the weapon is on "Safe" the trigger "clicks" about 1/16 of an inch and goes no further.  It does not fire in the "Safe" position.

When the weapon is on "fire" there is no clicking, its just smooth.

How did I do??? I have never done a trigger job before, nor have I read any instructions on how to do it, but it just seemed to make sense after I figured out how everything fit and worked.

Wow,

    Do you think since it works that it is ok?

The only thing that [b]really[/b] concerns me is the 1/16 jump while on safe. When you pull the trigger while on safe, is it just the trigger that clicks or does the hammer move too?? If there's any forward hammer movement, I'd be getting replacement parts handy....

Two notes on your procedure....

-- the sear surfaces should always have sharp edges. No matter how far the trigger has been pulled, there should be absolutely nothing that could prevent it returning to it's starting position. Rounded contact surfaces could act like a cam and bind the mechanism. (at the exact wrong time, of course)

-- Most trigger parts are only surface hardened. If you removed more than a thousandth or two, you might have removed the hardened layer. This will let the parts wear faster. I'd look into re-hardening those surfaces.

I don't think you did anything potentially harmful by the polish job but it sounds like you no longer have a "hard" safety.

The safety is a trigger blocking type and the back portion of the trigger slips under the safety cam, blocking its movement when on.  Sounds like you have a little clearance there, allowing the trigger to move slightly.

You can build up the pad on the trigger or replace parts.  Keep in mind you want this surface hard so unless you use a hard surfacing brazing rod, it will wear.  Also, if you do decide to build the surface, keep the sear surface cool, preferably by hanging it in water so only the rear leg is heated.

When I installed my JP trigger, I had a devil of a time installing and had to remove the safety.  It was a very hard safety when first installed but has loosened up quite nicely with operation.

[size=2]RANGE REPORT:

    Thank you all for responding.  I took the rifle out to the range today to test it out.  This is what happend.

1.  60 rounds semi auto with 1 second delay between shots.  No malfunctions.  Everything operated normally.

The only thing is that it surprised me each time I pulled the trigger.  Probably because it engages easier.

2.  60 rounds semi auto, squeezing as fast as I could.  Again no malfunctions or extraction problems.  

The only thing is that on two occasions while I was firing there was what seemed to be a two shot burst inbetween trigger pulls.  I did not check to see if I could do it on command.

In response to the trigger clicking 1/16th of an inch on "safe".  No the hammer does not move, just the trigger, and it does not fire.

OK.  Now tell me how bad I screwed up.  I am here to learn, and the damage is already done.  I feel like a real dumb a$$[/size=2]

Hey Newguy,,,I was going there, the two or more shot burst as I was reading your post.NEVER, Never, round any of the trigger/sear/hammer engagement points. thats why you were more surprised than usual with the trigger today, and that's why those points are smooth and should have a sharp edge to them. You may be able to restore the contact surfaces and breaking edges by matching the angle of the old notch and working it a little at a time with a fine flat stone. please don't use sandpaper around a knife anymore..... spand about 5 or 10 dollars, get a couple of nice flat stones and do your trigger work that way. it's worth the investment of a few $ to protect your rifle and possible prevent other bad things from happening. Also don't be bashful about asking here first before undertaking something you are unfamiliar with, there's plenty of help around and we won't think anyone stupid for asking. Have fun and keep exploring....

NewGuy, You just gave your rifle a burst mode!  Just kidding [;)] be safe and listen to these guys.  They know what they are doing.

[size=2]Wow, Thanks everyone.  I think I will just get a new hammer and trigger and NOT MESS with it!  

I did notice that when I was shooting my groups were a little to the left.  Would messing with the trigger have caused this?

Also would messing with my trigger mess up my firing pin or bolt carrier?  The trigger is solidly in there and there is no play.  I couldn't really tell but I think there are NEW marks on the hammer near the top where it hit the firing pin.

Dang, I had to go and mess with it.  I couldn't leave well enough alone!

Thanks all[/size=2]

new marks on the hammer are from your burst mode excursion, has to do with the hammer basically following the bolt/carrier into battery and all the other things that happen when the hammer is let to it's own devices. Pulling to the left was probably due to you not knowing what to expect and flinching or just holding different on the foregrip. I assume you're right handed? It's probably just flinching anyway. New trigger assy sounds like a good idea and then if you want to smooth some of the mating surfaces thats ok just keep the edges sharp to start with. Then later try some other stuff. [;)]

Sounds like a nice machinegun you have there if I where you i'd find the nearest lake real fast, since you just told the world bout your new creation.

Instead of $5-$10 for a couple of stones go $35 for a Lansky knife sharpening kit.  Nice collection of small flat stones with handels, not to mention one heck of a nice knife sharpener.

Hey, man, we all learn somehow.  You are not a dumbass.  I personally have learned more from tinkering with (and sometimes damaging) stuff that anywhere else.

[size=2]Thanks all,

    Well I certainly did learn a valuable lesson!  I will replace my trigger and hammer.  

    Is what Butthead said true?  I had no idea that modifying an existing trigger would fall into that catagory.  What about all those "GAT" trigger enhancers that they always sell at gunshows?  Would that be the same?

Thanks,
[/size=2]

I'm taking bets that NewGuy tries it again with his new parts.  Any takers....?

I wouldn't worry too much about what "Butthead" said. The issue is intent and function. You were not intentionally modifying the trigger group to get that result (bursting) and it is pretty obvious since it is not a regular or controllable thing. It's no different than having any other parts in your posession that have been ground wrong or are literally worn to the point of failing to engage. Which is the main issue here, failure to engage. A full auto trigger group works different than what you did, that's the uncontrolled erratic semi-burst mode. Use the parts you're taking out to prastice honing on and seeing how things meet up in there. You may even be able to redo them to servicability.    [beer]

Thanks again,

    I can assure you that I did not intend to have the result I ended up with.  I was just trying to make the action smoother.  I thought it would help my groups.  Anyway, I am removing the trigger and hammer tonight and ordering a new set.

I am going to take 8531SGTs advice and try to fix what I messed up.  I will not try any home gunsmithing that requires modifying parts until I know what I am doing now.  

Man, this is eating me up.  I can't stand things not being right.

Live and Learn I guess.

Thanks Again!

NEWGUY,

Cheer up. Just take a deep breath and relax. You've just walked where hundreds, if not thousands of others have treaded before.

At this point the toughest part is waiting for the replacements.

Besides, if it wasn't for US the parts industry wouldn't very be happy!

Now at least you probably know how your AR functions. That's more than we could say for the majority of 'black beauty' lovers.

In my business if you are not making mistakes you are playing it safe and aren't really trying hard enough.
I wouldn't beat myself up too much for this, you had the guts to tear into it and try to improve it, you already know far more about your gun than many others. Listen to the advice given, and try again, the worst that will happen is that you will have to order more parts and to be honest I'll bet that this time you walk up to perfection in smaller steps and it will come out mint. Enjoy.

Now that you know that the trigger and hammer have been modified so as to provide multiple shots with one pull of the trigger, you are in violation of section 922.  Dump those parts.  You may not possess them.

I guess we should re name this article to " How to Full Auto your AR". Just kidding.

I would imagine when your baby is back to normal you will have a better understanding of the trigger system as compared to the average AR owner.  

I had a similar experience with a Colt Government 1911 with a hair trigger courtesy of your truly. She's fine now, pulls at 2.5 lbs.

We live, we learn.

Parts are gone.  Now I have to sit and wait for a new trigger and hammer, but I guess I did it to myself.

    Thanks Cyberian,  I don't quite feel as bad now other than the fact that the end result was not what I intended which ultimately led to a violation of section 922?

[kill] make sure you keep your tin foil hat on too. That way they can't read your thoughts and know where you tossed the parts. Somebody's a little paranoid me thinks... [spank]