I want to make my bushmaster trigger crisp and the pull around 5 pounds.

Looking for advice on how-to and if pic are available that would be great to.

Also, tool needed.

Thanks ahead of time.

Here's a thread on what to be careful about, and some links on how to ;[url=ar15.com/forums/topic.html?b=3&f=12&t=162900]15min trigger job?????[/url]

your better off leaving that job to someone that knows what their doing.

Exactly.  My advice is don't do it yourself.  Have a gunsmith do it, or you could really screw up.

just mess with the springs. if you mess it up you pay 9 dollors for new ones. i did mine and its still pops every primer(mostly federal is what i use).  pull is scary light. much lighter then i wanted but it works great.

my trigger spring has the bend mod and the hammer spring has had one complete leg removed.
again this works fine and 9 dollors is all it takes to bring it back to stock configuration

Ryan, then you're paying about $5 too much for springs!  I get hammer and trigger springs for $1.50 - $2.00 each.

The problem is, some gunsmiths think they know how to do trigger work on AR15's, and it is not like pistol work.  They pull out the stones and start hacking in on the trigger and hammer, and the AR15 had serious problems.

The 15 minute trigger job is very simple and it works great.  I've done the job to 3 rifles so far.  None of my trigger jobs ended up with a "scary" trigger.  I've never had a misfire with factory ammo on any of the rifles.  Never weighed the pull but in each case it was much lighter than the factory set up.  Definitely take the advice of others who say "don't stone or hand polish, just follow the polishing instructions on the web site.  Definitely lighten up the hammer.

You may also want to consider the set screw through the pistol grip hole to take up some of the slop.  Worked great for me.

If you want about a 5# pull, using the 15 Min Trigger Job, do the light polishing (read the method) and modifying ONLY the hammer spring as described.  Do not modify the trigger spring, and you will have something about 5#.

Easy method to measure trigger pull:

Get an assistant.

Get an empty 1 gallon milk jug.  

Make sure the rifle is empty.  Temporarily remove the pistol grip.  Be careful to not lose the safety detent and detent spring.  Work the bolt to cock the hammer.

Tie a piece of cord to the trigger and the handle of the milk jug.  It should make a long loop thru the trigger and handle of the jug, NOT just one run of string with a little loop on each end.  Hold the rifle VERTICALLY.  As you see, the grip was removed to prevent the cord from rubbing on the grip, holding it out at an angle.

Have the assistent SLOWLY add water to the milk jug with a measuring cup or whatever.  

Stop adding water IMMEDIATELY when the hammer drops.

Now, ignoring the wt of the milk jug and cord (you can weigh them if you have the means, but consider them to weigh 1 oz.) measure via measuring cups the amount of water in the jug.

OK, now one gallon of water weighs 8.33 pounds, or 133.3 oz.  Do not confuse weight oz with FLUID OZ.  I will abrieviate FLUID OZ as "fl oz."  Also, there are 128 fl oz in one gallon of water.

Therefore, the wt of one fl oz is 1.04141 oz / fl oz.

Take the amount of fluid oz of water, and multiply times 1.04141 oz / fl oz.

So, if it took 67 oz of water to drop the hammer, then

67 fl oz  x  1.04141 oz/fl oz  =  69.775 oz

69.775 plus 1 for the jug, = 70.775 oz

70.775 oz divided by 16 oz/lb = 4.42 lb pull.

Got it?

Fine tuning the trigger pull:

For only moderate reduction in trigger pull, first do modifications only on the hammer spring, without touching the trigger spring.  Once you get to the point where you have clipped one leg of the hammer spring, as described in the article, go no further.  NOTE:  Do not touch the other leg of the hammer spring at all.

You may try first, not clipping the hammer spring leg at all, and simply bending ONE leg only, a little.  This should get you down to the 6# range.  Clipping the leg as described will get you down to 5# range.  I do not advise bending both legs, only modify one hammer leg.

Do the above without bending the trigger spring legs.  Once you have gone as far as clipping the right leg of the hammer spring, only THEN should you do any modifications to the trigger spring.

You can fine tune the trigger pull from the 10# range to below 4#.

Be VERY careful adding a set screw to take up sear engagement.  It is very easy to get doubling or even an accidental discharge.  I do not advise this.

I have done the 15 minute trigger job on two rifles.I am not unhappy with the results. It does make the trigger a little light for me. Next time I will use some of the ideas here.

Can someone post a link for The 15 min, trigger job?
Thanks

[url]http://www.geocities.com/molonlaberkba/triggerjob.html[/url]

I hope its hot. Just follow the instruction and you will have no problems. If you are using quality parts in your lower(Colt,Bushmaster) you can skip the polishing part. I have done this on 20 to 25 AR and not had anybody ask me to put back in the stock parts yet. We shoot all kinds of ammo also with no F.T.F.

Thank you ARK.
I have a Bushmaster with a real gritty trigger pull and will be putting a Mega lower together with parts from an M&A parts kit.

A Free Man, I did the setscrew deal last Friday night, by the time I filed the rear of the trigger to get the selector to work correctly, the disconnector grabbed it's hook in the hammer without my finger on the trigger.

Is this a common downside to the setscrew modification??  I could file the bottom of the disconnector, but at this point I'm about to say 'screw it'.  Any advice gratefully appreciated.

Thanks

-hanko

The AR15 is already a Corvette Stingray among civilian rifles.  A hotrod, a high performance item.  We need to keep it safe.  When I wrote up the trigger job article I was hoping that people would be satisfied with an improvement in trigger feel without in any way becoming unsafe.

Yes, what you describe is one of the problems with adding the setscrew.  The other is the rifle potentially doubling.  Now, the geometry of the whole thing is off.

That is why I did not advise or describe any further modifications, just KISS.

If you modify the disconnector now, and later the sear wears such that you need to increase sear engagment, the disconnector may not catch the hammer during semiauto fire.  You have several potential ways to make your once safe rifle malfunction.

Remove the set screw, replace modified trigger.  Sorry, but that is my advise.

If you are looking for reduced sear engagement, but still proper functioning, I advise you to buy the JP trigger and hammer.  They are engineered to have the proper functioning when set up as per instructions.

AFM, thanks for the quick response & your expertise.  Setscrew is gone, trigger will get replaced manana' as soon as the gunshop opens.

-hanko

hanko:  You might want to get a very short setscrew, one about the same length as the thickness of the receiver where you removed the screw.  Degrease the hole and put a little locktite on the screw and use it to fill the hole, to keep dirt out.  Just a thought.

AFM, good tip.  I bought 4 setscrew's 1/4 inch long.  I'll give it a try.  Thanks.

-hanko