I saw a video of a guy who used really fine sandpaper like that...similarly, I've heard of people using manicure files/buffers.

Can anyone comment on the difference between something like this and using a ceramic/stone for sharpening (maybe they tried this method on a FCG in one rifle, but a stone on another)?

I just did this. Used 2000 grit on the contact surfaces. No more than 30 seconds finger pressure sanding and it took most of the grit feeling out. (PSA CLassic  LPK)

I did the polishing work today. I'm considering buying the JP springs, but this is just a plinking/zombie rifle. I don't know if I really want that light of a break.

Anyway, I IMd Aubie1 for some set screws. I'm fully capable of going out and finding the screws myself, but there's no need for him to have nearly 100 screws lying around...

The polishing did such an amazing job. I've polished triggers before, but this is incredible. The CMMG FCG was so gritty, I almost didn't feel the take-up. The trigger just seemed to jump when squeezed.

Now the take-up is actually noticeable and smooth as silk. I'm looking forward to taking out most of it.

Thanks for all the good posts on this, guys!

Oh, and I was pleased to find my Spike's lower already tapped through.

Alright, I compromised a little on the trigger springs. I went with the JP 4.5# springs.

Depending on how well this works, it just might make this mod my standard trigger on any further builds.

I just put in the JP 4.5# springs and polished the surfaces. So much smoother and lighter now!

I ordered the set screws from BoltDepot.com, should have them tomorrow. If that takes care of the excessive creep, I will be a very happy camper. Will be heading to the range tomorrow afternoon!

Thanks to all who posted for this mod!

Edit: Forgot a couple things. I bought a replacement hammer, chopped off the excess with a cutoff wheel, and installed with the new springs. Saving the original parts. Also my Colt was already threaded all the way through for the set screw.

I did the grip screw mod as well, had to tap my PSA lowers, no big deal..... Ended up having to notch out where my safety contacts the trigger too. I used a sanding drum on my dremel to make it work.
i used 1000grit wet/dry paper, I put the paper down flat on my granite counter top, a drop of oil and started doing figure8 motions with it(checking it frequently)  to get the tooling marks off the face of my trigger. For getting into the tiny little gap in the hammer, i folded a piece of 1000grit paper over an edge of a old license plate an went back anf fourth with it till the machine marks vanished. after i finished the 1000grit, i busted out the dremel and some mothers mag wheel polish and a dremel buffing wheel. took MAYBE 15 seconds per surface to bring them to a mirror finish. I bent the spring legs with a pliers to lighten the pull some. had to play with it to get it right. I dabbed a bit of moly grease on the surfaces and assembled it. and been good to go since.

Also, did this for a buddy who had an "outa spec" FCG. i ended up doing the same as above, and having to fiddle with the disconnector timing, since his bad FCG would double very consistantly when letting go of the trigger. i took a few thousandths off the front of the disconnector to get it to engage sooner and bite better. To date, hes put over two thousand rounds through my "BUBBA JOB" trigger and no doubles or failures, no light strikes. seems legit
Great mod, defiantly worth doing

Ok, today I finished the job with the set screw to remove the creep. Much better. Went to the range and did some testing. All is fine!

I need a lot more practice. Shooting 100 yards from the bench with a sandbag using iron sights, the best group was with .223 MSR fusion 62 grain. Lake City 5.56 55gr and Remington .223 55 gr was just a little larger group.Still experimenting with ammo to find the best...

I just ran through the sear polishing side of things and wanted to share my experience. I ended up using an 8000 grit wet-stone for use with knife sharpening.  I gave it a couple spritz of water, made sure the sear was flush against the stone and gave a few strokes with finger pressure only...worked like a dream...and due to the fineness of the grain, hardly took any metal off of the sear.  I didn't need to polish it afterwards either...the 8000 grit stone did that too.  The rigger is now nice and smooth, with a crisp break, and no grit.

Question, since this modification changes spacing in the FCG, (e.g Robbing Peter to pay Paul) should the hammer "hit/contact" the disconnect during the cycle? In my hand I have a complete lower, as I pull the trigger the hammer is released as normal, however I noticed that as I pull the hammer back to reset the cycle it goes down, on its way back up it barely touches the disconnect. At this point my finger is completely off the trigger. I have adjusted the set screw back out to where no contact can be made between the hammer and disconnect unless I am holding the trigger.  When I do adjust it this far out, it defeats the use of the set screw as I'm back to where I started with the junky trigger.

I am not sure if this minor contact is a issue. Any help is greatly appreciated.

Instead of playing Russian Roulette with a set screw that first takes up slop between the pins and the bores in the receiver, trigger and hammer and second lessens engagement why not sell the hammer and trigger on eBay, GunBroker et al and put the proceeds towards a safe setup? DPMS makes a drop in two stage setup with springs for $99.95 delivered.
Frankly if you have to ask what the set screw does and cannot figure it out in your head then you should not be adjusting any crucial components that could allow a projectile to unexpectedly exit the muzzle around 3000 FPS and cause some innocent bystander and their friends and family to have a very bad day, etc.
On the safer side of DIY...Toss the weaker spring remedy to cure an ailing trigger as weak springs increase lock time and when least expected they'll encounter a stubborn primer. You can lighten some hammers a bit, do it in a way that flattens the hump portion above the claw and will not interfere with the cam movement between the hammer and carrier.
The myth going around about polishing away the hardened surfaces on the hammer and trigger is amusing. Just like it's OK to say Merry Christmas it’s OK to polish contact areas that under a microscope look like a mountain range.
Without using the springs take a dab of fine valve grinding compound and apply it to the hammer and trigger and install both in the receiver using stock pins. Manually operate the hammer and trigger by applying pressure to both as the trigger is pulled. Repeat until you're quickly bored and remove the pair and clean. Apply a drop of oil to the contact surfaces and repeat the process and clean again. A suitable high speed buffing wheel and compound gives a slick finish. Other than making sure everything is squeaky clean and using a lubricant that stays put the only thing left to do would be to remove the hammer J-Spring and replace the stock pins with .156" diameter JP Anti-Walk Pins then dry fire the weapon a few times to settle the components.
BTW...The best lower kits I've encountered with nicer trigger pulls have been made by CMMG. And for those who are stuck on using set screws: Some black 1/4"-28 set screws may not be compatible with the receiver threads and require running the screw through a die. DPMS Two Stage...

What's the difference between a musician and a pizza? One can feed a family of four.

It's only unsafe if you don't understand the mechanics of how the trigger works. I'd debunk that further for you but we've done that several times already in this thread.

The point of this entire thread has become to educate users to that end and I believe it accomplishes that.

Omit the word "only" and your opening line becomes the one and only fact that matters. Nine pages of omni-directional instructions, questions and opinions debunks any assumption that this thread has turned unskilled individuals/users into machinists, mechanical engineers, gunsmiths, etc. Unless hands on instruction is provided the bottom line is, "It's unsafe if you don't understand the mechanics of how the trigger works."

Some guy at a range near here almost shot another member in the back with a unsafe AR15 trigger.

It had the set-screw in the lower mod,and the sear had practically zero engagement.

The shooter said he did the work himself,and that he heard about it on the internet

Fixed.

Read all nine pages and didn't see this asked so if I missed it I apologize in advance.

Anybody using this trigger mode on a lower that is used with a 22LR conversion or multiple uppers (9MM, 7.62R)? Wondering if messing with the hammer will mess up the option of using multiple caliber uppers with a single lower?

One last questions very similar, anybody using this trigger mode with a JP Speed Hammer on a lower that is used with a 22LR conversion or multiple uppers (9MM, 7.62R)? Wondering if messing with the hammer will mess up the option of using multiple caliber uppers with a single lower?

That guy was an idiot then.
There are 15 steps that could have probably prevented that.

I have yet to see any measurements of these so called results.
Please put science to it.

Qualitative Data vs Quantitative Data
pi/2

I read through all 9 pages of this thread and have seen several posts referring to before and after measured results. Trigger pull before, trigger pull after. Amount of take up before, amount of take up after. Are any of the guys working for a major AR Manufacture that could do scientific testing, DOUBT IT! Besides most of ones weapons trigger feel is objective and not measurable. If it feels better, smoother, easier to shoot, then job accomplished and those things are mostly personal which doesn't lend them to scientific study.

So if its all about the science and not the results, why aren't you doing the mod and measuring/documenting everything then posting the results since it seems like that is somehow some must have thing.

Just getting the tooling marks off the trigger assembly mating surfaces is a big help over stock. The grinding gravel uneven feeling will be gone. Owning and shooting a tricked out 1911 all the time, a stock AR15 trigger feels worse then the trigger on my favorite cap gun when I was 5 years old.

Great thread. Thanks.

I Did this to gun and I love it


http://youtu.be/akDN3fNUzAs

My advise is if you want a Quality trigger BUY IT. Most people don't realize that most trigger groups are just Case Hardened. Maybe .007-.015 deep. Polish too much and you are screwed. Take 1/2 of that hardness away, and you've lost 1/2 if your triggers life. Change the angles. Now you are really screwed!
You might not like my advice. But it's coming from a T&D Maker with over 30 years of experience.
I've worked with metal my whole life.
I didn't just fall off a turnip truck. I'm also the kind of guy that likes to work on things myself. But I draw the line sometimes.

7 bucks and change to my door and I got 20....enough to do me for awhile. well worth it in my time and gas.  
https://www.boltdepot.com/Product-Details.aspx?product=8905

Next week I will compare side to side 3 trigger pull weights.
Factory Bushmaster untouched with CLP. Just Curious.
PSA LPG with polished parts, set screw, and JP Reduced Power Yellow Trigger Spring ONLY with CLP. No before and after...Sorry already polished.
PSA LPG Before and after, Polished, set screw, JP Reduced Power yellow spring kit (both), Bobbed Hammer. CLP.

For a better point of view
https://youtu.be/xh2FjzVVIZY

Just did this mod on one of my carbines. I bobbed the hammer, polished the sear surfaces with a stone, then 1,200 grit and finally 2,000 grit sandpaper. Installed the JP yellow springs and tapped the receiver for the 1/4" set screw. I'm extremely happy.

My groups are the same as yours with my .20 Vargtar and I haven't done the trigger job yet. I have all of the bits and look forward to doing the mod. hopefully it'll shrink the group's smaller.