One-Piece 76/760 Trigger Bar

[Jim in Texas]

An aspect of the 76/760 design that I never liked is the three-piece trigger bar made from stampings that are riveted together, so I decided to experiment making a one-piece trigger bar.  

While I was at it, I also decided to make the new trigger bar wider so it almost fills the width of the trigger housing.  I reasoned that this should allow the trigger bar to engage the full width of the sear and help to keep the trigger bar from getting pushed at an angle.  In turn, I think this will help to minimize wear on the trigger bar and sear, as well as providing a more consistent trigger pull.  

Here are a couple of photos of an original trigger bar next to the experimental one-piece version.  Thoughts or comments?

 

[M17ap]

Do you plan on making a run of these. I would be interested in purchasing one.

[Rekraps]

Very interesting, will this fit the M76? Also, the issue with the OEM trigger bar was that it "wore down" at the mating surface of the bar and the sear, resulting in misfires etc. Andrewski fixes this with hardened welds, reshaping the trigger bar end etc. so the gun can run 10K with no issues. What kind of steel are you using? Is it as hard as the sear metal?

 

I too would be interested.

[BillinBama]

Count me as interested too, we can't have too many M76 parts makers!

[Jim in Texas]

I ~assume~ this design would work in a S&W, but have only tried it in a single MK760, so I do not have definitive answer.

I opted to make this experimental part from 4140PH, which I understand is in the range of 28-32Rc.  I figured/reckoned that would be hard enough to be reasonably wear-resistant, without being hard enough to damage the sear.  (The sear looks like it would be harder to make than a trigger bar.)

I am purely a hobbyist who wants to share the results of his experiments with other enthusiasts, as well as learn from their input.  I intend to leave professional design and manufacture to someone more qualified.

 

[Rekraps]

Thanks, put me on the list for one!

[Remo Williams 1]

Awesome work Jim. 

[Jim in Texas]

I took a couple of photos to better show the relative width of the original and experimental trigger bars compared to the sear.

[Rekraps]

On 5/16/2025 at 11:30 AM, Jim in Texas said:

I took a couple of photos to better show the relative width of the original and experimental trigger bars compared to the sear.

This sear/trigger bar design, solid or OEM seem problematic from the start. The sear recess is very shallow AND rounded, while the OEM trigger bar is itself rounded making for failure to happen likely. Your solid trigger bar has a sharp 90 degree angle at the sear interface, yet the sear still has it's OEM rounded mate. I wonder if a touch of grinding to make the sear interface perpendicular to the "new" trigger bar would make the engagement more secure/solid.

[StrangeRanger]

The tip of the trigger bar as first manufactured is sharp for as long as it lasts; and sometimes that's not very long.  According to the one that I measured before I drew up my version of a replacement it's about 2 degrees acute, i.e. cut back to 88 degrees from perpendicular.  The contact point is at the bottom of the sear notch and it is sharp as well.  The radius at the top of the sear notch keeps the trigger pull from stacking as it disengages.  It's basically a just bizarre design that relies way too much on maintaining the hardness of the trigger bar tip.

[Rekraps]

On 5/19/2025 at 9:57 AM, StrangeRanger said:

The tip of the trigger bar as first manufactured is sharp for as long as it lasts; and sometimes that's not very long.  According to the one that I measured before I drew up my version of a replacement it's about 2 degrees acute, i.e. cut back to 88 degrees from perpendicular.  The contact point is at the bottom of the sear notch and it is sharp as well.  The radius at the top of the sear notch keeps the trigger pull from stacking as it disengages.  It's basically a just bizarre design that relies way too much on maintaining the hardness of the trigger bar tip.

Which explains the multiple and sure to happen failures. Andrewski used a hardened weld to reshape the trigger bar on both my 76's so I won't have to worry about this issue till waaaaay after I die.

[Don.]

12 hours ago, Rekraps said:

Which explains the multiple and sure to happen failures. Andrewski used a hardened weld to reshape the trigger bar on both my 76's so I won't have to worry about this issue till waaaaay after I die.

My wife’s new boyfriend is going to love what I leave behind, lol!