Sigma Trigger mods(Caution)

Back by demand

caution springs can fly and pins can fall and roll where you cannot find them.

Disclaimer
this information is provided with Caution slow methodical modification and testation. The Results will depend on Your work I will not be liable for your actions which may result in damaged parts or possible injury.

Before doing modifications it would be wise to purchase spare parts of parts which modifications are planned to occur on.
spare parts can be acquired by
Smith and Wesson
Brownells
Numerich's/E Gun Parts
sometimes auctions at gunbroker/auctionarms

Wolff AKA Gunsprings.com has aftermarket springs as well

this will not have much effect on guns that suffer from a crunchy trigger.

if you have a very crunchy trigger either send the gun into S&W or find a smith that can stone the sear and striker clean.

more you use the gun better the springs will let up. the springs new are designed to last many thousands of rounds and possibly years of service modifications will reduce such life but lighten the trigger effect modifying the springs will simulate many thousands of rounds of ammo. however springs after modification and exposure to heat or cold may suffer sudden failure. modifications should be no substitute for shooting such firearm verifying reliable function tolerant parts.

when removing the trigger/locking block pin
push the pin from right to left.
apply tool to right side of pin dont forcefully push it. grab the slide stop and pull it up to remove tension from the spring and slightly raise it under the locking block so the pin may continue to pass through it same time apply small amount of pressure to the pin with your right hand
when you get the slide stop just right pin will slide free.

reinstall the pin from the left side towards the right.


I strongly recommend against sandpaper for polishing its way to easy to sand unevenly and remove more metal which could put parts out of spec and more prone to malfunction. Stones should be used sparingly and certainly not in a dremel.

wire wheel at slow rpm's with felt tip slow rpms and progressively faster. hoppes gunsmith polishing compound can make things nice and wont remove too much metal when used lightly and cautiously. carefull touch can produce good results.










add grease,oil or paste to contact surfaces.
I usually use light oil but one day tried grease and it was much smoother.



teflon dry lube and polishing can leave parts
with reduced friction and easier cleaning



outer sear spring left,inner spring right.
outer spring may have double coil loop at the ends.

striker spring top,outer sear spring middle,inner sear spring bottom and torsion left. another spring which could potentially be modded is the striker safety spring but that is a critical one for safety.

Alert
Springs after stretching/compression may be strong for little while this will pass with use as the spring has been weakened final results will take a while SO GO SLOW TEST OFTEN.

Stock Sigma Striker spring weight is 4.75 lbs
wolff manufacture reduced striker spring for glock that has 4 lbs that will fit the sigma
they also have a spring for sigma that is 3.75 lbs. they also have a reduced power striker safety spring which could lighten the trigger as well.

reduced strength springs are only recommended for target/competition use.

DO NOT DO ANY MODIFICATIONS IF YOU DO NOT FEEL COMFORTABLE DOING IT FEEL FREE TO TRY AND ASK A SMITH TO DO THE WORK.

Back by demand

caution springs can fly and pins can fall and roll where you cannot find them.

Disclaimer
this information is provided with Caution slow methodical modification and testation. The Results will depend on Your work I will not be liable for your actions which may result in damaged parts or possible injury.

Before doing modifications it would be wise to purchase spare parts of parts which modifications are planned to occur on.
spare parts can be acquired by
Smith and Wesson
Brownells
Numerich's/E Gun Parts
sometimes auctions at gunbroker/auctionarms

Wolff AKA Gunsprings.com has aftermarket springs as well

this will not have much effect on guns that suffer from a crunchy trigger.

if you have a very crunchy trigger either send the gun into S&W or find a smith that can stone the sear and striker clean.

more you use the gun better the springs will let up. the springs new are designed to last many thousands of rounds and possibly years of service modifications will reduce such life but lighten the trigger effect modifying the springs will simulate many thousands of rounds of ammo. however springs after modification and exposure to heat or cold may suffer sudden failure. modifications should be no substitute for shooting such firearm verifying reliable function tolerant parts.

when removing the trigger/locking block pin
push the pin from right to left.
apply tool to right side of pin dont forcefully push it. grab the slide stop and pull it up to remove tension from the spring and slightly raise it under the locking block so the pin may continue to pass through it same time apply small amount of pressure to the pin with your right hand
when you get the slide stop just right pin will slide free.

reinstall the pin from the left side towards the right.


I strongly recommend against sandpaper for polishing its way to easy to sand unevenly and remove more metal which could put parts out of spec and more prone to malfunction. Stones should be used sparingly and certainly not in a dremel.

wire wheel at slow rpm's with felt tip slow rpms and progressively faster. hoppes gunsmith polishing compound can make things nice and wont remove too much metal when used lightly and cautiously. carefull touch can produce good results.










add grease,oil or paste to contact surfaces.
I usually use light oil but one day tried grease and it was much smoother.



teflon dry lube and polishing can leave parts
with reduced friction and easier cleaning



outer sear spring left,inner spring right.
outer spring may have double coil loop at the ends.

striker spring top,outer sear spring middle,inner sear spring bottom and torsion left. another spring which could potentially be modded is the striker safety spring but that is a critical one for safety.

Alert
Springs after stretching/compression may be strong for little while this will pass with use as the spring has been weakened final results will take a while SO GO SLOW TEST OFTEN.

Stock Sigma Striker spring weight is 4.75 lbs
wolff manufacture reduced striker spring for glock that has 4 lbs that will fit the sigma
they also have a spring for sigma that is 3.75 lbs. they also have a reduced power striker safety spring which could lighten the trigger as well.

reduced strength springs are only recommended for target/competition use.

DO NOT DO ANY MODIFICATIONS IF YOU DO NOT FEEL COMFORTABLE DOING IT FEEL FREE TO TRY AND ASK A SMITH TO DO THE WORK.

very good info, mrapathy!!! i do believe a lot
of new sigma owners will benefit from this.
i polished my sear with 800 then 1200 grit
sandpaper with a couple drops of remoil, then
used a dremel with polishing compound...it really made a noticable difference! for those who might be considering this....do try it yourself!! it's not as hard to do as you think!!

MrA, does your pistol have 2 springs on the striker? A skinny one inside the white sleeve and the heavy springin front? Some people tell me that they only have one spring. I have 2 Sigmas both late models one has the spring the other doesn't.

my bad. I should wake up before replying

Negative, I indeed mean the striker. There is a smaller spring that appears to remove slack when the striker is at rest. My SW9GVE has the 2nd spring and the striker doesn't rattle when the striker is at rest. My SW40G doesn't have the 2nd spring and the striker floats freely when the striker is at rest.

In your photo of all the parts laid out you have the white sleeve still on the striker. The 2nd spring is in that white sleeve around the striker. It looks like there may be one on yours in that picture.

one spring for striker is new to me both my VE's have 2 springs sorry. forgot that spring was there its function is minimal keeps the striker from free floating around about a 1/16th to 1/8th of inch. when the striker catches the spring the second spring behind the cap has reduced tension.

could call the factory see if its supposed to be there or not. another thing could be the design was changed elsewhere. could be limited to serial number range.

another mod that can make the trigger pull nice is taking some fine sand paper then sanding the trigger smooth motioning from top of trigger to bottom. carefull using a dremel with felt tip as it can easily melt the polymer. best to remove the trigger from frame

my triggers started out 10-12 lbs did bunch of shooting and dry firing brought them down some wore the parts in some down to 8-10 lbs smoother less mush or spring. I tweaked things slowly and tested at the range my guns have 6-7 lbs pull much smoother pull and I can shoot the gun a hell of alot better. my main intention is defense gun so I went slow and bought spare parts and have put many rounds in nothing of mine will fail anytime soon.

I've taken mine apart and using Flitz, a dremel and a slower speed drill done a preliminary polish. My sear had some serious machining ridges. The flitz didn't polish them away, but it is better. I plan on reassembly and shooting some more before tryng a second polishing pass.

Two questions. 1) What polish besides Flitz have you tried in case I need something more aggressive for the sear ridges.

2) On re-assembly how would you suggest reconnecting the trigger return spring. When its hooked to the metal trigger arm loop, the other end is unreachable. Should I try getting it on the pin first then using hemostats pull it back to the drilled hole in the trigger arm?

Thanks for the great info!

dont believe the sear is machines but more of an extruction or MIM metal injection molded part.

hoppes gun metal polish though really be carefull cause metal polish will remove metal if you get careless with it your part will get out of spec.

Stretching springs will ruin them. I wouldn't trust a stretched striker spring any further than I could throw it.

On re-assembly how would you suggest reconnecting the trigger return spring. When its hooked to the metal trigger arm loop, the other end is unreachable. Should I try getting it on the pin first then using hemostats pull it back to the drilled hole in the trigger arm?

Click to expand...

Thanks

make sure the trigger arm is loose have the sear module out.

insert the pin so the slide lock is caught then start working the trigger into alignment with the pin. dont feed the pin all the through the trigger. feed the pin enough so your ready to install the spring.

put the spring in place them grab the trigger arm and pivot it towards the front of the pistol the spring loop should line up with the pin and require no tension. then pivot the trigger arm back down and install the sear module.

Thank you so much for all your valuable information and assistance. I got the Sigma back together a little while ago and I am amazed at how much better the trigger feels. The gritty chattery pull is much smoother. It feels like a different gun.

Thanks for the detailed info, MrApathy. I purchased a Sigma last Monday, went to the outdoor range Tuesday, put 40 rds through it, and quickly realized that something had to be done.

Came home and found your post and went and did it right away. I polished everything up really well, and removed the torsion spring from the bottom of the sear assembly - I don't have my CWP yet, so I won't be carrying it.

Since then I have put 210 rds through it without the slightest hiccup. My accuracy is much improved from the smoother action, and I imagine it will only get better. Thanks again for the info - it has definitely helped this beginner out!

I really do advise for a good amount of firing the weapon stock and getting replacement parts of what has been modded to practice with the Sigma stock and modded. the mod is a handicap
the sigma can help you develop skill its a tough gun to shoot there is value in that.

shooting the gun stock does help wear in the trigger though can also wear in your hand and arms which is not such a bad thing.

the right thing is not always whats easy.

Hey MrApathy I seen your post on Sigma trigger mods, and I have to say, I'm impressed with it...I'm a retiered Marine, and now I work part time with the local sheriff's dept. I was a fire arms instructor, DMR, and a trained sniper, so I know a little bit about guns,I'm a smith&wesson man also, I bought a sigms 40gve two years ago, at a local gun show, and came home and did the same thing you did, and I have to say my sigma came out sweet, no problems, good to see other gun toting modifiers If you want to chat sometime email me at [email protected] Semper Fi Do or Die, I hope everybody out there on the forum is praying for our boys overseas!!!!!SGTMOE

Hey Mr Presspics, in responds to your question about the springs on the sigmas, I have a sigma 40GVE and it has two springs on the striker, I think the older sigs had one spring, and when they upgraded the sigs to make a better pistol that was one of the things they did, just for information, I did the same trigger job that MrApathy did on his and I have to say, I have one sweet 40 cal. and I would sell it for a 1000 dollars, turned out to be a very good pistol and I will have to put it into my collection....anyway have a good one.....
SGTMOE USMC RETIRED SEMPER FI DO OR DIE

Thanks SgtMoe. I pulled apart both of my Sigmas and took a closer look at the striker assemblies. The striker sleeve on the 9mm has a pocket for the 2nd spring to fit into. The .40 striker does not have that spring pocket and would not accept the 2nd spring. I guess that they changed it along the way.

I have just completed this trigger work on my new Sigma, thanks very much to MrApathy. I'm pleased with the results.

What I did:

-Dis-assemble and polish everything as in apathy's posts. Instead of a wire wheel, I used sandpaper: 400, 500, then 1000 grit, followed by dremel felt wheel with polish. I stoned the sear and striker mating surfaces with a set of stones I have for a 1911, there were noticeable ridges on them before I dressed them. Everything was done to a mirror finish.

My sear's curved rear surface (which brings it "down") also had some noticeable machining marks which I first dressed with a fine diamond file.

-Clipped the "redundant" coil off top and bottom of the larger (outer) sear spring, left the smaller (inner) sear spring as-is.

-My striker safety plunger had an internal ridge in the spring pocket which caused a discernible "twoing" when depressing it. I de-burred this with a drill bit and tiny diamond round stone. This plunger is made of HARD material!

-I also polished all pins to a mirror finish. One took off and went down a heater register in the floor doing this, by some miracle found and retrieved it

-The lower sear holder "twist" spring was slightly bent looser, by 0.037". This was not easy and required pushing it down into a Panavise while mounted on an appropriately sized pin-punch.

-A light coating of "militec" grease was applied to all contacting surfaces.

I have a high-tech way of measuring trigger pull, a Fish Scale and a string. While I don't really trust the actual readings I do trust the "relative" readings. Before mods: 15.5 lbs , after mods 14 lbs.

This sure doesn't seem like much but it feels so much better. I thought it felt pretty smooth before, but now it feels like a "Kahr" trigger only heavier. Of course some of this could be wishful thinking but given how much I smoothed the contact surfaces, it makes sense.

Having this pistol detail stripped made me appreciate the real quality of its parts and manufacture.

EDITED to correct nomenclature mistakes (striker vs sear)

Question ,
How do you replace the striker spring ? I got mine in the mail today. I cleaned up the sear last night and that took a lot of the gritty trigger away.I sure am glad I found this form!
Thanks Norm