Maximizing the Life of a 76/760 Trigger Bar

[Jim in Texas]

As most 76/760 owners have come to realize, the trigger bar in this design tends to wear.  Fortunately, Nav Gunner has made some new trigger bar and sear sets, and plans to make future production runs.  However, he cautions that "life is life" and there's no guarantee with respect to future availability. 

So, how do you maximize the life of your trigger bar?  I am not an engineer or a gunsmith, but it seems to me that a simple step might be not using the “semi” setting on the selector.  Here is my thinking:

When the gun is in “full,” the trigger bar pushes forward as shown here, which causes the sear to release the bolt.  

There is a lot of contact area between the trigger bar and sear.  Additionally, the trigger bar and sear remain in contact with each other the whole time.  I do not see a lot of opportunity for excessive wear when the selector is in “full.”

The situation is different, however, when the selector is in “semi.”  In that setting, the trigger bar initially pushes forward, which causes the sear to release the bolt.  But then, the trigger bar moves down to disconnect from the sear.

As the trigger bar makes this second movement, all the load between the trigger bar and sear is concentrated at the very top corner of the trigger bar, which then has to slide out of the notch in the hardened sear to perform the disconnect function.  

This top corner of the trigger bar is where we see the problematic wear.  

It seems to me that minimizing use of the “semi” setting on the selector would help avoid excessive wear on this top corner, which in turn would help to maximize the life of the 76/760 trigger bar.  The “semi” setting could still be useful in some circumstances, but an experienced shooter might want to minimize its use and instead focus on trigger control to get singles or doubles.

Thoughts or comments?

 

[Rekraps]

Hey Jim, great post. I have owned three S&W 76's (currently have two) and all three units required trigger bar work which struck me as odd given the condition of the guns. It was my assumption (uh oh!) that these guns, even though not really designed for long-term use, would at least cycle through 5,000 or 6,000 rounds before things went bad. All three of my guns appeared to be be low round count so I was baffled. 

My solution was of course to ship them off to Andrewski who reworked the three piece bar and welded high strength steel to replace the softer OEM stuff. So they will be good for 10K rounds according to John. 

Now to your question, I strongly suspect that virtually everyone who owns these guns uses them almost exclusively on FA, thus the idea that limiting use of the semi-auto function would not really impact the wear, as most of us have experienced trigger bar failure. From my perspective, the issue is the tiny surface area on the sear and sharp edges. Even on FA the sear moves slightly which imparts wear on the much softer trigger bar end surface and so like a match, keep rubbing and "poof" it's gone. 

My recommendation is a hardened trigger bar, either Andrewski or some other source if you can find it. 

Glad to  respond!

[BillinBama]

Navgunner (Austin Meeks) has a great trigger bar replacement on his website as well as other M76 items, our community needs to support him as he try to make parts for our guns that are not available anymore. 

[Jim in Texas]

I just realized that my photos did not make it into my original post.  Here is an illustration of the trigger bar movement when the selector is in "full."

 

[Jim in Texas]

Here is an illustration of the trigger bar movement when the selector is in "semi."

 

[Jim in Texas]

And here is top corner of the trigger bar that takes all the load when the trigger bar slides out of the notch in the hardened sear to perform the disconnect function in "semi."

 

[Jim in Texas]

BillinBama - I absolutely agree with supporting NavGunner and with the idea of getting spare wear items while you can.  Just ask anyone who was there, but never "got around to it" in time with OEM parts.  

I am just trying to avoid going through those spare parts any faster than I have to.  Strike while the iron is hot, but also take care of the anvil you already have.  (smile)

[Jim in Texas]

Rekraps - Yes, I agree that the trigger bar does move slightly in the sear notch and is going to experience some wear when the selector is in "full."  A number of people I shoot with tend to switch to "semi" when the scoring dictates that the percentage of shots fired that are "hits" counts as much as the total number of "hits."  Those are the experienced shooters I think would be most at risk of the accelerated wear associated with shooting in "semi."

On your worn trigger bars, I wonder if those were higher-round count guns that were just well maintained.  I have seen these guns that have gone through well in excess of 10 cases of ammo that looked near new (other than worn rifling) because they were range-use guns that the owner did not abuse and did proper preventative maintenance along the way.  Just a thought.

[Rekraps]

Based on my experience, both guns were low count guns. Makes no difference now, I've had them both worked.