Old Split Sear Trigger

[krxm21]

Old, but new to me. Rem 700 style Split sear trigger with three adjustment screws, at the bottom. So which one does what? Sear is not holding.

 

[STS]

That is a Hart trigger I believe.

 

[1911nut]

Gemini says:

Adjusting a trigger is one of those tasks that feels high-stakes because, well, it is. When dealing with Hart triggers (often found in Remington 700-style actions or custom benchrest rigs), the goal is usually to achieve that "glass rod" break without sacrificing safety.

Before you start, ensure the firearm is completely unloaded and the bolt is removed if possible during the initial setup.

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The Three Adjustment Screws​

Most Hart-style triggers utilize a three-screw system. Looking at the trigger housing, you will typically find:

1. Top Front Screw: Pull Weight (Tension)
2. Bottom Front Screw: Over-travel
3. Rear Screw: Sear Engagement (Creep)

1. Sear Engagement (The "Creep" Adjustment)​

This controls how much the trigger has to move before the sear releases.

• To Adjust: With the action cocked, slowly turn the rear screw clockwise until the firing pin drops. Then, back the screw out (counter-clockwise) about 1/4 to 1/2 a turn.
• The Goal: You want the sear to held securely, but with minimal movement required to trip it.

2. Pull Weight​

This adjusts the spring tension against the trigger blade.

• To Adjust: Turning the top front screw clockwise increases the weight; counter-clockwise decreases it.
• The Goal: For benchrest, this is often set very light (measured in ounces), but for a field rifle, you generally don't want to go below 2.5 lbs for safety.

3. Over-travel​

This controls how far the trigger moves after the shot is fired.

• To Adjust: Turn the bottom front screw clockwise until the trigger won't fire, then back it out slowly until it fires reliably. Add another 1/8 turn for a "safety margin."
• The Goal: Minimal movement after the break to prevent disturbing your aim.

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The Critical Safety Tests​

Once you think you're finished, you must perform these tests with an empty chamber:

• The Slam Test: Open and close the bolt vigorously several times. The firing pin should not drop.
• The Drop Test: (With the rifle pointed in a safe direction) Bump the buttstock firmly against a padded floor. The sear should remain engaged.
• The Safety Check: Ensure the manual safety still engages and disengages smoothly and that the rifle cannot fire while the safety is "On."

Pro Tip: Use a tiny drop of clear nail polish or blue Loctite on the threads once you’ve found your "sweet spot" to ensure the screws don't drift due to recoil.

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Would you like me to find a specific manual or diagram for a particular Hart model (like the 1.5 oz Benchrest vs. the Sporting model)?

Yes do that.

To dive deeper into the Hart trigger adjustments (typically produced by R.W. Hart & Son), it is important to distinguish which version you have. Hart produced several models, ranging from the light 1.5–2 oz Benchrest models to heavier Sporting versions.
For the most common Hart 3-lever Benchrest triggers, the screw locations and functions are slightly different from a standard factory Remington trigger.

Hart Trigger Screw Mapping​

On many older Hart models, the adjustments are found on the bottom of the trigger housing, near the trigger shoe itself:

Screw Position	Typical Function	Adjustment Result
Front Screw	Sear Engagement	CW: Decreases engagement (less creep). CCW: Increases engagement (safer).
Middle Screw	Pull Weight	CW: Increases weight. CCW: Lightens weight.
Rear Screw	Over-travel	CW: Decreases travel after break. CCW: Increases travel.

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Step-by-Step Refinement​

If you are working on a precision/benchrest build, follow this sequence:

1. Clear the Sear (Front Screw): With the action cocked, turn the Front Screw clockwise until the firing pin drops. Then, turn it back counter-clockwise roughly 1/8 to 1/4 turn. This sets the "crispness."
2. Set the Weight (Middle Screw): Adjust the Middle Screw to your preferred pull. On Hart benchrest models, this can go as low as 2 oz. If you feel the screw getting too loose, stop—you are losing spring tension, which can lead to "slam fires."
3. Stop the Over-travel (Rear Screw): With the firing pin dropped (dry fired), turn the Rear Screwclockwise until it touches the trigger. Then back it out just enough (about 1/8 turn) so the trigger can still release the sear reliably when cocked.

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Vital "Pro-Tips" for Hart Triggers​

• Cleaning is Mandatory: Hart triggers are precision instruments. Before adjusting, many shooters recommend flushing the housing with Lighter Fluid (Zippo/Ronsonol) or Naptha. This removes old oil or grit that can make the trigger feel "mushy" or cause it to fail to reset. Do not use heavy oils, as they attract dust.
• The "Slave Pin" Trick: If you ever need to remove the trigger from a "glue-in" benchrest stock, you may need a short slave pin (the exact width of the trigger housing) to hold the internal levers in place while you drive out the main retaining pins.
• Thread Locking: Once you are satisfied, Hart triggers must be sealed. Use a tiny dab of clear nail polish on the screw heads. This prevents them from vibrating loose while allowing you to break the seal later if you need to adjust it.

Caution on Benchrest Triggers: If yours is the 1.5 oz to 2 oz model, do not attempt to use it for hunting or field use. These are designed for controlled bench environments; they can and will fire if the rifle is bumped or the bolt is closed too hard.
Would you like me to try and find a visual diagram of the internal lever arrangement, or are you ready to start the mechanical tests?

 

[steve210]

Needs cleaning probably, spray it with some brake kleen

 

[aussiedave]

That is the early version . The later ones had the trigger piece dovetailed into the adjustment block . A grub screw in the trigger piece to held it in place.