Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
BCM
User Panel

Page AR-15 » Build It Yourself
AR Sponsor: bravocompany
Trigger work? (Page 2 of 5)
Page / 5
Link Posted: 10/5/2011 8:15:41 PM EDT
[Last Edit: MGP] [#1]
Just finished the trigger i had to take .008" off the topside on the back of the trigger to get the saftey to work, no creep function tested perfect ,breaks clean at 4.25lbs.

ETA: I used a course knife sharping stone and then followed it up with a fine stone.
Link Posted: 10/5/2011 9:32:24 PM EDT
[#2]
Originally Posted By MGP:
Just finished the trigger i had to take .008" off the topside on the back of the trigger to get the saftey to work, no creep function tested perfect ,breaks clean at 4.25lbs.



Outstanding.

Hope my previous replys weren't too condescending sounding, but now that this is a stickied thread, I'd rather reply as if the person asking didn't know what they were doing.  Just no telling what the experience level of people reading it is going to be.

Please keep everyone up to date with how it holds up.

Mine has a couple thousand rounds through it now with zero issues, love it.

Someday I may invest in a drop in trigger just to compare, but for the time being I'm not inclined to drop the dime since this trigger setup is so nice compared to stock.

Link Posted: 10/5/2011 9:43:29 PM EDT
[#3]
Originally Posted By kwrangln:
Originally Posted By MGP:
Just finished the trigger i had to take .008" off the topside on the back of the trigger to get the saftey to work, no creep function tested perfect ,breaks clean at 4.25lbs.



Outstanding.

Hope my previous replys weren't too condescending sounding, but now that this is a stickied thread, I'd rather reply as if the person asking didn't know what they were doing.  Just no telling what the experience level of people reading it is going to be.

Please keep everyone up to date with how it holds up.

Mine has a couple thousand rounds through it now with zero issues, love it.

Someday I may invest in a drop in trigger just to compare, but for the time being I'm not inclined to drop the dime since this trigger setup is so nice compared to stock.



Not at all i would rather get a well explained response even if i know how it works. And will do on keeping everyone up to date. Thanks Mike

Link Posted: 10/10/2011 2:37:45 AM EDT
[#4]
Followed all the steps in this thread on 3 lowers last night. Pulled them apart, polished the trigger, tapped the grip screw, bent the trigger springs, clipped the hammer spring on the right side, and chopped the hammers. Pull is about half of what it was factory(feels like the 3.5lb in my 1911), has 1/8" take up intill the nice clean break. Shot them all today with out one issue. Great work and pictures here guys, this really works.
Link Posted: 10/13/2011 10:47:18 AM EDT
[#5]
Would polishing the strike face of the hammer help anything?
They are on some performance FCGs.

It would probably just provide less friction from the bolt carrier though right?
I know it's not a trigger pull question buy while I'm polishing is it worth the extra time/effort?
Link Posted: 10/13/2011 1:18:09 PM EDT
[#6]
Originally Posted By BadAxxFireFighter:
Would polishing the strike face of the hammer help anything?
They are on some performance FCGs.

It would probably just provide less friction from the bolt carrier though right?
I know it's not a trigger pull question buy while I'm polishing is it worth the extra time/effort?


I see no gain by doing this operation.

Link Posted: 10/13/2011 1:26:48 PM EDT
[#7]
Yeah I figured, but thought it was worth asking.   Had no clue if it'd do anything.
Link Posted: 10/17/2011 7:15:35 PM EDT
[#8]
Worked perfect on my DPMS. didn't even need the tap, it was already threaded all the way through.

Thank you Sir
 You are bad ass
Link Posted: 10/24/2011 10:37:03 PM EDT
[#9]
Originally Posted By kwrangln:
Since arf keeps archiving threads and the search sucks, I'll throw up some pics again..

1.  Tap the grip screw hole all the way through.
http://i277.photobucket.com/albums/kk58/kwrangln/new%20ar%20build/newar47.jpg
http://i277.photobucket.com/albums/kk58/kwrangln/new%20ar%20build/newar54.jpg

2.  Take your run of the mill LPK hammer and cut the crap out of it to lighten it up.  Touch it up with a spray of paint when you're done.  An object at rest stays at rest until acted upon.  A heavy hammer takes more force to accelerate than a light hammer.  Since I use light springs, the light hammer allows them to accelerate it to full travle speed alleviating light strikes.
http://i277.photobucket.com/albums/kk58/kwrangln/new%20ar%20build/newar26.jpg
http://i277.photobucket.com/albums/kk58/kwrangln/new%20ar%20build/newar27.jpg

3.  Add in some light weight springs, they are cheap and work great.
http://i277.photobucket.com/albums/kk58/kwrangln/new%20ar%20build/newar31.jpg

4.  Clean up the machining marks on the sear surface.  These are what gives you that gravel road trigger pull.
Before.
http://i277.photobucket.com/albums/kk58/kwrangln/new%20ar%20build/newar28.jpg
After.
http://i277.photobucket.com/albums/kk58/kwrangln/new%20ar%20build/newar29.jpg
My tool of choice is a small ceramic knife sharpening stone.  Very fine cut and a nice flat surface.  You don't need to take much off, and be careful to keep the sear flat on the stone, you don't want to change any angles.
http://i277.photobucket.com/albums/kk58/kwrangln/new%20ar%20build/newar30.jpg

5.  Put it all together.  FIrst you'll need a set screw and some blue locktite.
http://i277.photobucket.com/albums/kk58/kwrangln/new%20ar%20build/newar48.jpg

Run that puppy up the grip screw hole untill it contacts the bottom of the trigger.
http://i277.photobucket.com/albums/kk58/kwrangln/new%20ar%20build/newar49.jpg

Hold the trigger to the rear and cock the hammer so that it is caught by the disconnector.
http://i277.photobucket.com/albums/kk58/kwrangln/new%20ar%20build/newar51.jpg

Then let go of the trigger and back out the set screw until the hammer falls from the disconnector to the sear.
http://i277.photobucket.com/albums/kk58/kwrangln/new%20ar%20build/newar52.jpg

Function check and adjust as necessary.  You may have interference issues with the safety, if so then use a round file to make a groove in the back upper surface of the trigger so the safety clears.  Once everything is good, set it aside and let the locktite set up.

6.  Go to the range and see just how good the trigger feels now, you'll be amazed.





I am a little apprehensive on a modified trigger just for safety reasons. Since you have been using this mod have there been any full auto episodes, double or triple fires. I don't want any problems at the range or when i'm clearing a building with a officer in front of me. Thanks again for your help.















Link Posted: 10/25/2011 12:14:47 AM EDT
[#10]
Originally Posted By BCSO-755:
Originally Posted By kwrangln:
Since arf keeps archiving threads and the search sucks, I'll throw up some pics again..






I am a little apprehensive on a modified trigger just for safety reasons. Since you have been using this mod have there been any full auto episodes, double or triple fires. I don't want any problems at the range or when i'm clearing a building with a officer in front of me. Thanks again for your help.





Not a single issue in over 2K rounds now.  The disconnector wasn't touched, and no angles were changed on the sear, so I don't expect any issues in the future either.  Trust me, if I ever do have an issue, updating this thread and warning people off will be one of the first things I do.

Link Posted: 11/11/2011 7:01:30 PM EDT
[#11]
After reading this post last night I decided to take a look at my trigger. You should know I've never even taken the trigger out of my AR before, so if I can do this I think most could too.

I found that I did have a indented trigger, you could feel it with your fingernail. I lightly wet sanded it with some 1000 grit and gun oil, then finished it with 1500 grit. I filed the hammer just enough to get rid of the rough spots, nothing too drastic. I also bent the hammer spring and installed a set screw to take up the slack.

I don't have a trigger gauge, but I can tell an improvement was definately made.

ben
Link Posted: 11/13/2011 9:30:14 PM EDT
[#12]
I did the set screw, cut the hammer, and jp springs approach.  I like it better than my rra 2 stage.  One problem.  No matter what i do the trigger pin keeps waking.  tried a new pin and made sure the hammer spring sat in the grove.  Still walking.
Link Posted: 11/14/2011 12:58:02 AM EDT
[#13]
Maybe a KNS pin kit would solve that problem.   They aren't expensive at all.
Link Posted: 11/14/2011 10:33:33 AM EDT
[#14]
Actually ordered jp pins. I don't like how the kns look.
Link Posted: 11/15/2011 8:20:15 PM EDT
[#15]
Finally got my AR out of the safe to shoot it a bit and didn't like the rough hard trigger pull, so after reading hear ,I polished the surfaces and bent the springs a bit , noticeably smoother, lighter and better but still has the pause but its very smooth now , not sure about wanting to go the set screw route as my AR is a late 70's SP 1 colt that I bought new in 80 , Its been a stored pretty much the whole time except for a few excursions (maybe 500 rounds) over the years. I'm mostly a handgun guy but  can't see not having a little time now with my AR as it's a classic and you can only do so much with the pistols. Any opinions etc. from any one that owns an early SP1. Thank You , Walther Zero
Link Posted: 11/26/2011 9:25:20 AM EDT
[Last Edit: Sawnoff] [#16]
Just pulled mine apart, spike's lower already tapped through
Polished up the sear a bit and put it back together till i get a screw later. Feels so much better already, that bit of polishing took all the gravel out
EDIT: Added screw with loctite after getting adjusted and slight filing on back of trigger for safety to clear. Didn't change spring or cut hammer, cost was only 78c for set screw.
Well worth doing,i now have a non gritty, shorter pull, very happy ...Cheers
Link Posted: 11/26/2011 8:37:55 PM EDT
[#17]
This is on my list of things to do.
Link Posted: 11/28/2011 10:15:06 PM EDT
[#18]
Can somebody post pic's of where & how to bend the springs? That makes the trigger pull lighter, correct? Thanks!
Link Posted: 12/1/2011 6:58:39 PM EDT
[#19]
Originally Posted By TexFF:
Can somebody post pic's of where & how to bend the springs? That makes the trigger pull lighter, correct? Thanks!


Sure thing:


I measured down from the ends about an inch and then used needle nose pliers to make the bends.
Link Posted: 12/4/2011 11:39:43 AM EDT
[#20]
When I did mine, I took all of the creep out with the set screw. After shooting it and discussing with a friend the debate on whether or not some creep is a good thing or not.

What is the consensus on this?

ben
Link Posted: 12/4/2011 11:21:38 PM EDT
[#21]
Originally Posted By esa17:
Originally Posted By TexFF:
Can somebody post pic's of where & how to bend the springs? That makes the trigger pull lighter, correct? Thanks!


Sure thing:
http://jfc17.smugmug.com/photos/i-fVvqBf8/0/L/i-fVvqBf8-L.jpg

I measured down from the ends about an inch and then used needle nose pliers to make the bends.


Thanks, did you cut some of the hammer off, too?
Link Posted: 12/5/2011 2:33:35 AM EDT
[Last Edit: Ryo] [#22]
Opps,  my bad,  forgot what this thread was about.
Link Posted: 12/5/2011 6:42:14 AM EDT
[#23]
Originally Posted By TexFF:
Originally Posted By esa17:
Originally Posted By TexFF:
Can somebody post pic's of where & how to bend the springs? That makes the trigger pull lighter, correct? Thanks!


Sure thing:
http://jfc17.smugmug.com/photos/i-fVvqBf8/0/L/i-fVvqBf8-L.jpg

I measured down from the ends about an inch and then used needle nose pliers to make the bends.


Thanks, did you cut some of the hammer off, too?


No, I did.  I'm a perfectionist and I've just not had the time to put in all the effort to make the hammer perfect once cut.  After the first of the year though, I'll give it a go.
Link Posted: 12/5/2011 11:28:16 PM EDT
[#24]



Originally Posted By Jason85:


this helped mine out alot



http://www.youtube.com/watch?v=sJegVLr1rEU&feature=related



http://www.youtube.com/watch?v=BVhJNEX6alQ
I fucking lost it when this guys phone started ringing.



Excellent post on this.

Thanks for making this thread. I will be looking over my stuff soon and

working on my triggers.





 
Link Posted: 12/7/2011 5:27:59 AM EDT
[#25]
My Areo lower was tapped all the way through, so made a set screw a 1/4 inch long from a bolt i cut off, made a slot for a screw driver with a dremel cutoff wheel, had to take a little metal off the back of the trigger where the saftey goes through, takes about a minute, loctite my homemade screw in place and presto, works like a charm, i also just bent my springs, just left it on the hammer and bent em backwards. This works folks.
Link Posted: 12/7/2011 7:33:10 PM EDT
[#26]



Originally Posted By dennyd:


My Areo lower was tapped all the way through, so made a set screw a 1/4 inch long from a bolt i cut off, made a slot for a screw driver with a dremel cutoff wheel, had to take a little metal off the back of the trigger where the saftey goes through, takes about a minute, loctite my homemade screw in place and presto, works like a charm, i also just bent my springs, just left it on the hammer and bent em backwards. This works folks.
My Superior lower has the hole tapped all the way so it got a set screw installed.



My Palmetto lowers have to be threaded. One set screw installed on that one.




Love this "mod"




My FFL had me feel the Stag LPK thats in his AR. Very smooth pull, nice and crisp too.





 
Link Posted: 12/14/2011 1:35:17 PM EDT
[#27]
Just for reference, since I haven't seen any mention yet:

I'm doing the full trigger mod on some DPMS kits that I've got.  My lower (Surplus Ammo and Arms) was already threaded through.  When I added the set screw I found that if I wound it in to take up all of the pre-travel it would hit the safety as expected, but what I also found is that it started catching the disconnector.  I manually cycled the hammer while backing the set screw off till it just cleared the disconnector.  It would then also just clear the safety.  Still has a bit of creep (maybe 1mm), but it's worlds better than stock (maybe 2.5mm of creep).  I'll be lightening the hammer and testing as soon as my JP springs show up. I want to run it with all types of ammo and a .22 dedicated upper to see how it works in those scenarios before I mod any of my other lowers.  I'll report back with my findings.  

I will say that just polishing the sear and installing the set screw has radically changed the feel of this trigger.  I can't believe how easy of a mod it was and what a huge difference it makes.

Thanks, guys...
Link Posted: 12/19/2011 10:27:05 PM EDT
[#28]
so the set screw takes up the creep but does it do anything for the over travel / reset?

i'm thinking about getting the adjustable mega trigger instead
Link Posted: 12/21/2011 12:16:21 PM EDT
[#29]
Did this mod today. Everything went great until I filed too much off the trigger where it interfered w/the safety. Now safety won't work & my trigger is trash. DON'T file too much off the back of the trigger. Other than that is gonna be a nice improvement once I do it all over again on the new trigger!
Link Posted: 12/22/2011 11:11:13 PM EDT
[#30]
Originally Posted By TexFF:
Did this mod today. Everything went great until I filed too much off the trigger where it interfered w/the safety. Now safety won't work & my trigger is trash. DON'T file too much off the back of the trigger. Other than that is gonna be a nice improvement once I do it all over again on the new trigger!


With my 2nd trigger I figured out where I went wrong. It is PARAMOUNT that you have the hammer cocked(FIRE) position before you decide how much to take off the rear of the trigger for clearance. If you don't have the hammer in the FIRE position you WILL take off too much.

***************COCK THE HAMMER BEFORE YOU MEASURE HOW MUCH TO TAKE OFF TO CLEAR THE SAFETY*************************************************
If it's not 'cocked' you'll take off too much. I never saw this point made in ANY of the trigger mod threads I read but it is paramount!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Link Posted: 12/23/2011 8:26:48 AM EDT
[Last Edit: MGP] [#31]
Originally Posted By TexFF:
Originally Posted By TexFF:
Did this mod today. Everything went great until I filed too much off the trigger where it interfered w/the safety. Now safety won't work & my trigger is trash. DON'T file too much off the back of the trigger. Other than that is gonna be a nice improvement once I do it all over again on the new trigger!


With my 2nd trigger I figured out where I went wrong. It is PARAMOUNT that you have the hammer cocked(FIRE) position before you decide how much to take off the rear of the trigger for clearance. If you don't have the hammer in the FIRE position you WILL take off too much.

***************COCK THE HAMMER BEFORE YOU MEASURE HOW MUCH TO TAKE OFF TO CLEAR THE SAFETY*************************************************
If it's not 'cocked' you'll take off too much. I never saw this point made in ANY of the trigger mod threads I read but it is paramount!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


Im not busting your balls but you have to have the hammer cocked to engage the safety its just common knowledge.You need to know how your weapon works before you go playing around with anything Especially  with the trigger.

Link Posted: 12/23/2011 12:28:18 PM EDT
[Last Edit: TexFF] [#32]
I know it has to be cocked to engage safety(I've owned several dozen rifles & ALL had to be cocked to have safety on) BUT I'm talking about looking thru the safety hole, w/the safety removed, to measure how much to shave off for clearance.
Link Posted: 12/25/2011 12:16:12 AM EDT
[#33]
Where can i buy the correct tap and set screws?
Link Posted: 12/25/2011 10:43:24 AM EDT
[#34]
Lowes or Home Depot sell them as will any local hardware store.
Link Posted: 12/30/2011 2:20:41 PM EDT
[#35]
I am in the middle of my first AR15 build.  I have a YHM stripped lower, and I got a PSA MOE Plus LPK.  
My intention before installing the kit was to do the trigger job, including the Set screw in the Grip screw hole, but I have to be honest...I don't feel any pretravel at all with it the way it sits.  
I measured the total travel at just under 3/16 of an inch, from start to break.  Is this unusual?  
I can't see why anyone would want it any shorter.  
The only thing I did do was install a set of JP trigger springs and that reduced trigger pull a noticible amount.  
I still have th upper to go, but it will have to wait a few months.  I have a 1911 on layaway at buds I need to pay off first....

I look forward to your comments
Link Posted: 1/4/2012 6:29:02 PM EDT
[#36]
ok quick question on this mod. when adjusting the set screw for the disconnector release.  I back it out until the disconnect releases the hammer to the sear.  now when checking the clearance between the disconnector and the hammer spur by pushing the hammer with my thumb is it ok for the two to touch (no trigger pull),  as long as the disconnector catches the hammer when trigger is pulled back and releases when trigger is released?  I have just a little bump in there between the two when thumb operating the hammer. but catches and releases just find every time.
Link Posted: 1/5/2012 1:36:50 AM EDT
[#37]
Originally Posted By AR15fan:
Where can i buy the correct tap and set screws?


ACE Hardware. Cheaper than anybody else and they carry everything.
Link Posted: 1/5/2012 1:40:29 AM EDT
[Last Edit: Espos1111] [#38]
Originally Posted By HenryinFlorida:
I measured the total travel at just under 3/16 of an inch, from start to break.  Is this unusual?  
I can't see why anyone would want it any shorter.  
I look forward to your comments


3/16 of an inch seems like a mile while "squeezing" slowly.
Link Posted: 1/11/2012 12:49:50 PM EDT
[#39]
Originally Posted By esa17:
I'm buying a new hammer and spring set today, along with some anti-roll pins I think.  

I've never tapped a lower before, what kind of lube do you use?  Any other tips for tapping the lower?


There are products out there for tapping like "Tap-Magic" - for aluminum they are basically kerosene. Diesel would probably work fine.
Link Posted: 1/13/2012 7:21:55 PM EDT
[#40]
This works pretty good. What # of trigger do you have now. Mine went from 9 gritty #'s to a smooth 5 1/2 #'s. Would like to get to 4-41/2#'s if I could. What would the next logical step be?
Link Posted: 1/29/2012 12:40:17 AM EDT
[#41]
I just installed a mega trigger on one of my training ARs that has a single stage trigger.  I normally run LMT two-stage triggers, but after trying Mega's trigger, I think I will be building single stage trigger/lowers with a Mega trigger.  Light and smoothe...

D.
Link Posted: 1/29/2012 8:59:21 AM EDT
[#42]
Originally Posted By shooter1950:
This works pretty good. What # of trigger do you have now. Mine went from 9 gritty #'s to a smooth 5 1/2 #'s. Would like to get to 4-41/2#'s if I could. What would the next logical step be?


just did this and got to a 4lb pull on every pull by using the set screw and stock trigger parts, JP enhanced spring kit and molygraph grease on the sear and disconnector contact points. I never touched the disconnector with a stone. don't have any way to measure travel but it ain't a whole lot.. this lower is for a 7.62x39 build, thats why I went with the enhanced spring kit.
Link Posted: 2/9/2012 1:23:07 AM EDT
[#43]
I just tried this and got the most horrible reset ever. The pull is great but when i let off the trigger is slow to let out to the point that it will slow down my rate of fire. Its like that even with the set screw backed all the way out. Could this be because of me bending the hammer spring by any chance? I ask because i thought maybe with that spring weaker it is having a hard time pulling the hammer off the disco. I personally think that its just bad parts. I got a new trigger and hammer for this just in case things went wrong(thank goodness), but my disconecter is from my old FCG that works just fine. Im thinking maybe the new hammer or trigger just dont like that disco. If anybody has any thoughts or experience with this problem, your advice would be appreciated.
Link Posted: 2/13/2012 10:30:29 AM EDT
[#44]
I installed the set screw in my lower, but only took it up to the trigger, I didn't file the slot to allow it to be set further in, and I also replaced my trigger group springs with the JPS 3.5 lb spring set.
Everything is working perfect and has very little reset travel.  Not sure why your's is slow to return.  You must have something rubbing.
Link Posted: 2/15/2012 8:55:16 PM EDT
[#45]
Originally Posted By sandmountaindriller:
I just tried this and got the most horrible reset ever. The pull is great but when i let off the trigger is slow to let out to the point that it will slow down my rate of fire. Its like that even with the set screw backed all the way out. Could this be because of me bending the hammer spring by any chance? I ask because i thought maybe with that spring weaker it is having a hard time pulling the hammer off the disco. I personally think that its just bad parts. I got a new trigger and hammer for this just in case things went wrong(thank goodness), but my disconecter is from my old FCG that works just fine. Im thinking maybe the new hammer or trigger just dont like that disco. If anybody has any thoughts or experience with this problem, your advice would be appreciated.


Be sure that the trigger return spring is correctly installed.
Link Posted: 2/16/2012 5:24:42 PM EDT
[#46]
I did this about two weeks ago with everything that the OP said to do aside from installing new springs...  Lowe's had everything I needed for the set screw and tap.  I found that I could put the set screw in as far as it would go until my trigger would ride against the safety.  I put it in there until the safety ground against the trigger then turned the set screw back one full turn and it worked perfectly!  Polished the sear and everything, holy smooth!  Love it!!!!!!!
Link Posted: 2/16/2012 8:14:09 PM EDT
[#47]
How does this affect the drop safe feature of the trigger group?  If you watch your hammer as you pull the trigger it moves from the interaction with the sear.  It  is in essence over centered and helps keep the weapon from having an AD if dropped or handled roughly. I really want to do this mod but don't want do it if it compromises the safety features of the design.
Link Posted: 2/17/2012 12:30:23 AM EDT
[#48]
Originally Posted By ErikS:
How does this affect the drop safe feature of the trigger group?  If you watch your hammer as you pull the trigger it moves from the interaction with the sear.  It  is in essence over centered and helps keep the weapon from having an AD if dropped or handled roughly. I really want to do this mod but don't want do it if it compromises the safety features of the design.


I drop tested my rifle a bunch of times after the mods and have yet to have the hammer drop.

Cock hammer, and mortar the stock on the floor a dozen times (collapse stock before hand so you don't break it), if hammer doesn't drop, you're good to go.  Same tests you should do when you assemble any AR.

Link Posted: 2/19/2012 10:59:52 PM EDT
[#49]
triger jobs are better left to a profesional.and remember.that if you happen to shoot someone with that weapon,it falls under modification.
Link Posted: 2/20/2012 12:40:43 AM EDT
[#50]
Originally Posted By cruz1911:
triger jobs are better left to a profesional.and remember.that if you happen to shoot someone with that weapon,it falls under modification.



With the ammount of "professional" trigger jobs that have had issues, I'll take my chances.

As for a modification, if you believe that then you better not ever add a red dot, flashlight, etc, it may make it easier to shoot someone.

Page / 5
Trigger work? (Page 2 of 5)
Page AR-15 » Build It Yourself
AR Sponsor: bravocompany
Close Join Our Mail List to Stay Up To Date! Win a FREE Membership!

Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!

You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.


By signing up you agree to our User Agreement. *Must have a registered ARFCOM account to win.
Top Top