Trigger Job?

[Troutguide]

So in preparation for the 12" Faxon barrels that are due to arrive any year now i am putting the finishing touches on my pistol build. I have a mill spec standard US made FCG that was really rough and tough so I ordered the JP reduced power springs. While researching how to improve trigger function with the new springs I read all sorts of articles and decided that I would bob my hammer and polish all the mating surfaces. So yesterday I did it I was very careful starting with 600 grit paper on glass and went all the way up to 2000 and then final polish with cloth wheel being careful not to round anything or change angles. While was at it I went ahead and bobbed the hammer with a cutoff disk and polished this surface as well just for good measure and smoothed the lower trigger corners so it feels nice on my finger. It feels great except for the creep that will be corrected, when the set screws arrive, for the grip/hammer prop up job.

So did I ruin my trigger by doing this? If you believe everything you read on the internet, like I do, you will be convinced that I have removed all the surface hardness and this thing will self destruct in a matter of a few shots, if I can get anything to actually fire due to light hammer strikes. So who has an opinion I can adopt as my own(I read it on the internet and remember I believe everything I read). Seriously, even if it is ruined it was fun to do and the trigger is amazing right now, I can't imagine I hurt anything for a hunting/play gun that will be shot a few hundred times a year.

I also opened up my buffer and removed the weight, cut it in pieces and reassembled with a small piece in the buffer held in the center with rubber tubing on either end. It now weighs ~1.75 oz. I am running a reduced power spring and light weight BC and have an adjustable GB to dial it in. Gun will weigh just under 5lbs before scope and full mag. This is my first AR BTW so I am a complete nube with lots of unwarranted confidence.

Thoughts please.
TG

[LRRPF52]

When I polish the mating surfaces of the trigger and hammer, I just use a cotton buffer wheel with polishing compound.

I would never consider using sand paper, as that is way aggressive to a hardened surface.

Bobbing the hammer is pretty normal, not a big deal for me on several trigger jobs dating back to 2003.

Reduced power hammer springs are a major cause of light strikes, especially in cold weather. I would expect to see light strikes with the steel case ammo, so just watch for that if you don't replace with a full power hammer spring.

The reduced springs for the disconnector and trigger return are fine, as long as the FCG passes the function test.

For the price of the LaRue MBT-2S, there is less and less incentive to mess with trigger jobs nowadays.

[bj139]

I just received my two Larue triggers yesterday and I really like the extra heavy hammer spring since I had many light strikes with one trigger I bought.

I used this on one of my milspec triggers and it smoothed it up considerably.

https://www.lowes.com/pd/PORTER-CABLE-5-...l/50171523

While at Lowes get this and screw it in the grip screw to reduce creep. Once you find it works OK apply Loctite and reinstall.

https://www.lowes.com/pd/Hillman-2-Count...ws/3012514

You may need a few washers or a shorter grip screw if it interferes with tightening the grip.

[Troutguide]

Thanks guys. I understand the concern with the hardened surface removal, hence my post. I was very light with the 600 then on to the 1000, it only removed the faintest tooling marks and polished the surface, this sandpaper is for paint finishes on automobiles so it can't remove much. How shallow is the actual hardened surface? How would I know if I did damage? Anyone actually see a trigger fail bc of this type of work, opposed to the continual warnings saying it is a possibility?

I used a similar buffing compound and a cloth wheel to final polish. Looking forward to hitting my Zwickey broadheads with it, should make "shaving sharp" easy after some good file work. As for these screws I thought I needed 1/2" so I ordered them. Lowe's only had the 1/4" you posted if the 1/4" work I would rather use that so the grip screw won't need so many washers.

The Larue trigger looks nice but I only have about $450 in this gun, so the price is still high for me, trying to do this on a thin budget. Maybe next year I can upgrade.

TG

[LRRPF52]

Be very careful when messing with taking up pre-travel of the trigger, as I've seen instances where the screw advanced and under fire, mistakenly turned the gun into full auto.

Whenever there is an adjustable feature on a Fire Control Group, once you think you have it dialed in super short and light, back that off by at least a quarter or half turn to avoid any problems, and make sure the thread locking compound holds up after exposure to oils.

[Troutguide]

Point taken, I will err on longer pull and I think the 1/2" set screw will be better for more loctite contact.

TG

[bj139]

I used the 1/4" screw on my Anderson lower. The threads seemed to run out and was hard to turn once the trigger started to move. I adjusted it up against the safety and then backed off about a quarter of a turn as LRRPF52 suggested. There is still a small amount of creep which is good for safe operation but the trigger is MUCH better. I have been using the Magpul plus grips which are rubber and they come with a shorter screw than stock so it all fit.

Edit: I had the red JP spring in for the hammer and just put the milspec hammer spring back in for reliability.

[just_john]

TG - have done a lot of these "trigger jobs", however .... I want a full mil-spec hammer spring ( as LR stated ) for max primer strike. You won't feel the difference on the trigger. I use a very fine stone to polish the seer surfaces and then some teflon oil on 'em. I got a 1/4" tap and run out the threaded hole that the grip mounts in and run a 1/4" long set screw up the channel before mounting the grip (and it gets a spot of loctite ). I also drill and tap a hole up between the lugs for the retaining pin and put another set screw with a soft tip up that way to take "most" of the play out between the upper and the lower. This hole comes out at the top end of the ramped grip mounting gussett. Then, I bob the hammer to reduce the orbital mass for improved lock time.
Doing this, I take out almost all of the creep and overtravel. Keeping the original mil-spec springs insures a solid primer strike an, since there is so little trigger travel, keeping the original trigger spring is almost not discernable.
You can get the set screws from Home Depot but I order 'em thru McMaster in Chicago - a lot cheaper and true MS quality. Overnight delivery as well.

[bj139]

Doesn't bobbing the hammer reduce the hammer force?

Light primer strikes may result.

[Troutguide]

Speed trumps mass when it comes to hammer strikes. Thats why we shoot 6.5 Grindel instead of 300BO too!!!

[mongoosesnipe]

i polished a crappy milspec trigger to decent on my first ar build once you get to a decent break where it doesnt feel like its grinding or catching its about as good as it gets with standard fair components, i thought it was fantstic until i bought a geissele high speed match trigger but thats a different animal on my last lower build i uses the anderson stainless trigger and hammer and i must say for a $40 lpk i was very impressed obviously its not a geissele but it was pretty good certinly good enough for plinking gun, i will probably try the larue on my next lower build

[derek45]

JP enterprises sells a really nice trigger kit

brownells has them for about $110

I've been using them for many years, without any trouble

much nicer than any USGI type parts.

[The Profit Joseph Sith]

JP enterprises sells a really nice trigger kit

brownells has them for about $110

I've been using them for many years, without any trouble

much nicer than any USGI type parts.

I've done one or two of these. Even bought four of the Anderson SS trigger and hammer kits to polish up (they are VERY CHEAP about $22 a set minus springs, pins and hardware) but I've kinda abandoned that idea in favor of good quality triggers. Score two HSNM DMR's for about $190ea and recently just ordered two of the Larue's (I want my MBT's ) they just had on sale with the chassis.

I've ALWAYS wanted to try the JP triggers I think if I get any more those will be next. JP makes great stuff. Definitely upper echelon.

I always used like a leather strop to hand polish mine. That way there no possible way to loose temper or hardening. And some fine like green SS high chromium polish followed by some ultra fine plastic/acrylics type polishing compound. I'm thinking lately I might have to make a small carriage with precision rods and bushings or reamed holes for doing this sort of work.

[just_john]

bj, speed = mass x ( velocity squared ) speed wins every time

[just_john]

bj - Oops! Energy = mass x ( velocity squared ). a small change in mass doesn't affect the energy nearly as much as a small change in speed. by reducing the mass of the hammer, it increases the speed significantly so the impact energy may actually be greater than before.

[Lastrites]

And that is why JP recommends a bobbed hammer for use with their yellow springs, for increase in speed.

[Troutguide]

Which is why I bobbed it. I used the yellow springs. If I get light strikes I will go back to the original hammer spring.

[bj139]

Maybe you should cut even more more off for greater energy.

There must be a reason the military specified a larger hammer with a big tail.

There is usually a reason for everyting that has certain specifications.

I switched back to the milspec hammer spring for my SHTF AR since I have had many misfires with reduced springs.

I just received 2 Larue triggers and the hammer springs are massive, stronger than milspec. Got me thinking.

[derek45]

the " big tail" was for the full auto sear

civilian hammers have the notch on the end ground off

JP takes it a step further

i have 3 or 4 of them installed,.....buy with confidence

JP is top notch stuff

[bj139]

Yes. I see. You can get greater hammer accelaration with less mass and with adequate reliability.

To the OP: I was led to this video by reading these posts. If JP uses sandpaper, it must be OK.

https://www.youtube.com/watch?v=37B7yGWPAi8

Another question about the OP: Why do this?

"I also opened up my buffer and removed the weight, cut it in pieces and reassembled with a small piece in the buffer held in the center with rubber tubing on either end. It now weighs ~1.75 oz."