Tri-Glide Trigger Bow - Fits different in SV than STI

[ExtremeShot]

My limited gun is a SV with a tri-glide sear spring and disconnector. My open gun is an STI with the exact same tri-glide sear spring and disconnector.

When I put the SV tri-glide trigger bow (with the ball bearing on the back) in my SV Limited gun, there is very little pretravel (so little that it causes doubles and hammer follow). When I stick the exact same trigger bow in my STI, I have all kinds of pretravel. Both guns have the similar red sti grips.

I eventually had to go to a standard SV trigger bow (with no ball bearing) in the SV Limited gun to get some pretravel and prevent the doubles and hammer follow.

Anyway, it's interesting that the tri-glide trigger bow will work in my STI, but not the SVI. Do you think the difference is in the frames? ....I guess the grips could be slightly different.

Darren

[pjb45]

You should send a PM to 'Whatmeworry'. He has some experience in this matter.

[BEDELLCUSTOM]

the inside of the grips where the trigger sits when it's all the way forward is possibly different, if the trigger sits more forward in one then it would provide more takeup or if you have different sears in the 2 guns the thickness of the legs of the sear will affect takeup, the thicker the legs the less gap between the disconnect pads and the sear legs would cause less takeup.

[scirocco38s]

the inside of the grips where the trigger sits when it's all the way forward is possibly different, if the trigger sits more forward in one then it would provide more takeup or if you have different sears in the 2 guns the thickness of the legs of the sear will affect takeup, the thicker the legs the less gap between the disconnect pads and the sear legs would cause less takeup.

exactly

[ExtremeShot]

It has to be the grips or the frames then, 'cause, as I said, the sears are exactly the same.

[Pat Miles]

I've found the same problem when fitting several SVI triggers into STI grips. Seems that the overall length of the SVI Trigger bow is longer than that of an STI. I've had luck in shortening the bow by reforming the front 90 degree bends to a slightly larger radius which shortens up the sides of the bow giving you more clearence for the sear. Go slow so you don't reform the bow too wide for the grip channels.

CYa,

Pat

[BEDELLCUSTOM]

one thing I forgot to mention also is that if you have 2 different hammers it will slightly change the position of the sear when the hammer is in the cocked position since the geometries of hammers are not all the same. Even though you have the same sears they may not have been cut the same when it comes to the primary and secondary angles on them. As Pat said the bows are usually longer on the SV triggers but not always, it seems like every one I get is different, that's why I usually remove the SV shoe from it's bow and fit it to an STI bow and that gives me a lot more room for adjustment.

[kgunz11]

I've found the same problem when fitting several SVI triggers into STI grips. Seems that the overall length of the SVI Trigger bow is longer than that of an STI. I've had luck in shortening the bow by reforming the front 90 degree bends to a slightly larger radius which shortens up the sides of the bow giving you more clearence for the sear. Go slow so you don't reform the bow too wide for the grip channels.

CYa,

Pat

+1

Learned this for myself the hard way. Same trigger you are having issues with, and I wanted to use the trigger so I refused to let it whip me, I knew it could be done. Cured the doubles, which I first thought was from the over travel screw. All it takes is a little tweaking. I also had to change the pressure on the left leg of the spring, with the new trigger bow tweaks it got REALLY light, like under 1lb light.

[ExtremeShot]

Yep, I agree about the hammers and the sears. In my case, again, I have the exact same hammer on both guns and I cut both sears the same way using a Power Series jig. Both sears have only been cut once.

Just for kicks, I switched the grips around and the results were the same. It appears the frames are cut a little different.

D

one thing I forgot to mention also is that if you have 2 different hammers it will slightly change the position of the sear when the hammer is in the cocked position since the geometries of hammers are not all the same. Even though you have the same sears they may not have been cut the same when it comes to the primary and secondary angles on them. As Pat said the bows are usually longer on the SV triggers but not always, it seems like every one I get is different, that's why I usually remove the SV shoe from it's bow and fit it to an STI bow and that gives me a lot more room for adjustment.

[ExtremeShot]

I solved the problem already. I just replaced the SV Tri-Glide trigger with a SV Standard trigger (with no ball bearing). That gave me the additional space I needed in the pre-travel to prevent the doubling.

I've found the same problem when fitting several SVI triggers into STI grips. Seems that the overall length of the SVI Trigger bow is longer than that of an STI. I've had luck in shortening the bow by reforming the front 90 degree bends to a slightly larger radius which shortens up the sides of the bow giving you more clearence for the sear. Go slow so you don't reform the bow too wide for the grip channels.

CYa,

Pat

[Pat Miles]

I lke th SVI trigger so I can use the short flat insert that fits my trigger finger. I've decided to start using the STI "gunsmith fit" trigger to avoid the above hassels. I just face off the front of the shoe to the length I want on my belt sander and then dress the face for smoothness. Less expensive alternernative.

CYa,

Pat

[kgunz11]

I solved the problem already. I just replaced the SV Tri-Glide trigger with a SV Standard trigger (with no ball bearing). That gave me the additional space I needed in the pre-travel to prevent the doubling.

Pretravel in the trigger should not be causing doubling, but the overtravel could be, is this what you mean? The pretravel is adjustable via the bendable tabon the trigger bow, overtravel is adjustable via the set screw in the trigger shoe. Not enough overtravel will cause the gun to "bump fire" or double, but then I guess not enough pretravel could do the same thing...

[00bullitt]

Actually pre travel has everything to do with doubling. Too little on a light trigger can cause trigger bounce. Which causes hammer follow and doubling if it skips the half cock notch. Too little overtravel can cause sear nose battering(sear nose contacts half cock notch because not enough clearance)and lead to premature sear wear which in turn can cause doubling from a poor mate(engagement)of the sear nose to the hooks.

Material can be removed from the back of the sear legs that mate with the disconnector paddle for increased pretravel if necessary.

Edited March 27, 2009 by 00bullitt

[kgunz11]

I guess pretravel and overtravel have a correlation between the 2 that can cause doubling. I'd think with enough overtravel zero pretravel would be fine, with little overtravel and little pretravel you could induce doubling.

[00bullitt]

With little or no pretravel,the sear legs are already under tension. It does not take much moving mass for the trigger to bounce and trip the sear with minimal sear spring pressure required to get sub 2.5# triggers. More sear spring pressure can negate the doubling but trigger pull weight increases. Getting a reliable sub 2.5# trigger brings all factors into play. Trigger weight and pre travel being part of it.

Edited March 27, 2009 by 00bullitt

[ExtremeShot]

With little or no pretravel,the sear legs are already under tension. It does not take much moving mass for the trigger to bounce and trip the sear with minimal sear spring pressure required to get sub 2.5# triggers. More sear spring pressure can negate the doubling but trigger pull weight increases. Getting a reliable sub 2.5# trigger brings all factors into play. Trigger weight and pre travel being part of it.

++1 Yep, what he said. I first started working on the sear spring. Even with a lot of pressure on the left and middle leg, it kept doubling. Then I noticed the lack of pretravel. There was virtually none. Even with the tab on the front of the trigger flush, there still wasn't much pretravel. After getting rid of the ball bearing trigger bow, I started getting some travel and bingo, no doubles.

[Josh Biondi]

one thing I forgot to mention also is that if you have 2 different hammers it will slightly change the position of the sear when the hammer is in the cocked position since the geometries of hammers are not all the same. Even though you have the same sears they may not have been cut the same when it comes to the primary and secondary angles on them. As Pat said the bows are usually longer on the SV triggers but not always, it seems like every one I get is different, that's why I usually remove the SV shoe from it's bow and fit it to an STI bow and that gives me a lot more room for adjustment.

Can you make we know how do you remove the SV bow and change it with a STI bow without destroy the trigger? I was unlucky trying this way...

thanks for your info

[TISCHLJ]

I fit a triglide to a couple older STI grips. These were used grips.

Seemed the SV was very senistive to how closely the trigger shoe fit in the opening TG from top to bottom.

The bow is fatter on the STI bow also- once I fit a different shoe to the triglide and made it fit the TG area tighter the trigger feel improved greatly and all creep vanished.

No problems with not enough take up. But again, the two grips I fit were approx 3 years old.

A newer STI grip I wanted to fit with a triglide gave me similar take up issues.

FYI

[rhebert]

Who noticed the problem ???

With little or no pretravel,the sear legs are already under tension. It does not take much moving mass for the trigger to bounce and trip the sear with minimal sear spring pressure required to get sub 2.5# triggers. More sear spring pressure can negate the doubling but trigger pull weight increases. Getting a reliable sub 2.5# trigger brings all factors into play. Trigger weight and pre travel being part of it.

++1 Yep, what he said. I first started working on the sear spring. Even with a lot of pressure on the left and middle leg, it kept doubling. Then I noticed the lack of pretravel. There was virtually none. Even with the tab on the front of the trigger flush, there still wasn't much pretravel. After getting rid of the ball bearing trigger bow, I started getting some travel and bingo, no doubles.

[ExtremeShot]

..........Officially, Mr. Rick Hebert of St. Louis, Missouri noticed the problem. .....Dang, now that you're lurking again on Benos, I better go modify all the other threads where I took credit for your work.

[n2ipsc]

...I've found the same problem when fitting several SVI triggers into STI grips. Seems that the overall length of the SVI Trigger bow is longer than that of an STI...

Spot on - excellent thread on this phenomena HERE...