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Sear lift

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On single shot rifles with an exposed hammer or revolvers I like to drill a small hole using a carbide bit just below the full cock notch and install a small length of drill rod secured by red Loc-tite. The rod is shortened in height to limit the amount of sear engagement which both reduces trigger pull weight and creep while maintaining full main spring strength.
In the first picture you can see the engagement depth is reduced half.
In a percussion revolver the sear lift hole and lift needs to be touching the full cock notch to work with the shorter hammer throw axis. It then needs to be sloped on the back angle so it won't trip on the trigger nose/sear as it cams up the lift to meet the reduced full cock notch.
 

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On single shot rifles with an exposed hammer or revolvers I like to drill a small hole using a carbide bit just below the full cock notch and install a small length of drill rod secured by red Loc-tite. The rod is shortened in height to limit the amount of sear engagement which both reduces trigger pull weight and creep while maintaining full main spring strength.
 

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On single shot rifles with an exposed hammer or revolvers I like to drill a small hole using a carbide bit just below the full cock notch and install a small length of drill rod secured by red Loc-tite. The rod is shortened in height to limit the amount of sear engagement which both reduces trigger pull weight and creep while maintaining full main spring strength.
In the first picture you can see the engagement depth is reduced half.
In a percussion revolver the sear lift hole and lift needs to be touching the full cock notch to work with the shorter hammer throw axis. It then needs to be sloped on the back angle so it won't trip on the trigger nose/sear as it cams up the lift to meet the reduced full cock notch.



Idaho Lewis left a write-up on the tc single trigger guns and his method for getting a reasonable pull weight. I’ve done this to three of my t/c’s with good results. Any thoughts Mike?

https://www.modernmuzzleloader.com/threads/tc-single-trigger-“trigger-job”.31395/
It is usually poor practice to lower the full cock notch as it makes the fly work much harder bouncing the sear over catching the half cock notch as it passes over. Instead of the sear nose impacting the top of the fly and being redirected over the half cock notch it hits the fly lower on the body making it absorb more of the force which wears both the sear nose and fly body faster. It especially shows up in fly-less sear trigger arrangements often catching the half cock or in semi-auto pistols going full auto.
The sear lift is light years ahead of shortening full cock notches because it does not mess with the sear/full cock notch, swing radius geometry. It does the same work from the top of the full cock notch height causing less stress on all related parts.
Shortening the full cock notch is actually rather dangerous on many fire arms and over stresses design limits of parts on those it is gotten temporarily away with, in my opinion.
 
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It is usually poor practice to lower the full cock notch as it makes the fly work much harder bouncing the sear over catching the half cock notch as it passes over. Instead of the sear nose impacting the top of the fly and being redirected over the half cock notch it hits the fly lower on the body making it absorb more of the force which wears both the sear nose and fly body faster. It especially shows up in fly-less sear trigger arrangements often catching the half cock or in semi-auto pistols going full auto.
The sear lift is light years ahead of shortening full cock notches because it does not mess with the sear/full cock notch, swing radius geometry. It does the same work from the top of the full cock notch height causing less stress on all related parts.
Shortening the full cock notch is actually rather dangerous on many fire arms and over stresses design limits of parts on those it is gotten temporarily away with, in my opinion.
Next time I have the Walker apart I'll try to remember to post a picture of how to configure a sear lift on a revolver hammer. I usually just nick the front of the full cock edge when drilling the lift purchase hole to make sure the trigger nose/sear will not trip on any gap left between the lift and full cock notch and then show how it needs to be tapered off at the rear so the trigger can cam up the angle to the reduced contact engagement.
 
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Idaho Lewis left a write-up on the tc single trigger guns and his method for getting a reasonable pull weight. I’ve done this to three of my t/c’s with good results. Any thoughts Mike?

https://www.modernmuzzleloader.com/threads/tc-single-trigger-“trigger-job”.31395/
Have notice on some TC tumblers that they were only case hardened, not through hardened. Removing .018” of steel to lower the full cock notch height will weaken the strength of the notch in addition to changing the geometry as @M. De Land mentioned. Doesn’t take much to break a tumbler. If you want to try, work the set trigger a number of times with the lock on half cock, but only if you have a spare tumbler.
 
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Have notice on some TC tumblers that they were only case hardened, not through hardened. Removing .018” of steel to lower the full cock notch height will weaken the strength of the notch in addition to changing the geometry as @M. De Land mentioned. Doesn’t take much to break a tumbler. If you want to try, work the set trigger a number of times with the lock on half cock, but only if you have a spare tumbler.
I’ve only done this with the single trigger models. The set trigger guns are just fine.
 
It is usually poor practice to lower the full cock notch as it makes the fly work much harder bouncing the sear over catching the half cock notch as it passes over. Instead of the sear nose impacting the top of the fly and being redirected over the half cock notch it hits the fly lower on the body making it absorb more of the force which wears both the sear nose and fly body faster. It especially shows up in fly-less sear trigger arrangements often catching the half cock or in semi-auto pistols going full auto.
The sear lift is light years ahead of shortening full cock notches because it does not mess with the sear/full cock notch, swing radius geometry. It does the same work from the top of the full cock notch height causing less stress on all related parts.
Shortening the full cock notch is actually rather dangerous on many fire arms and over stresses design limits of parts on those it is gotten temporarily away with, in my opinion.
I have three guns I’ve treated thusly. I’ll keep an eye on them. With fingers crossed.
 
I have three guns I’ve treated thusly. I’ll keep an eye on them. With fingers crossed.
MY guess is that mod will work for a long time on any gun not used a great deal like a competition arm would be before showing stress. Time and use are what shows up any weakness in original design or those caused by us gun mechanics.
I've on occasion had to repair/replace my own ideas of design improvements over the years.
I've had two pistols take off on me with shortened full cock notches and lightened springs.
You can tell when a magazine load of spent cartridges are all still hanging in the air at the same time , your jaw drops open and your eyes bug out ! 😄
 
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I’ve only done this with the single trigger models. The set trigger guns are just fine.
Pretty sure TC used the same tumbler for both the single and set trigger versions, as the locks were the same. The difference was in with the triggers. My point was that the process of reducing the full cock notch depth essentially removed the case hardening and the steel supporting the notch, while changing the geometry of the lock’s functional components. Basically shade tree gunsmithing that works until it doesn’t.

One thing I’ve done to reduce trigger pull on the single trigger TCs was to replace the sear spring with one made with smaller diameter spring wire while keeping the free length of the spring the same.
 
Pretty sure TC used the same tumbler for both the single and set trigger versions, as the locks were the same. The difference was in with the triggers. My point was that the process of reducing the full cock notch depth essentially removed the case hardening and the steel supporting the notch, while changing the geometry of the lock’s functional components. Basically shade tree gunsmithing that works until it doesn’t.

One thing I’ve done to reduce trigger pull on the single trigger TCs was to replace the sear spring with one made with smaller diameter spring wire while keeping the free length of the spring the same.
I still have my first TC Hawken. I ringed the 50 cal barrel shooting a maxie ball that worked forward on me while moose hunting and replaced it with a .54 cal Douglas barrel before they quit making muzzle loading tubes. I never liked double set triggers that fired from the front so rebuilt mine to a single trigger firing from the back of the trigger bow. If memory hasn't failed me I used all the same parts, removed the set sear and just welding in a shank extension of the firing trigger and adjusted engagement and pull weight.
I never like that the Douglas barrels are made of 12L14 but it is very accurate and I take care to not short start or over charge it. It likes a .530 ball, .018 shirt felt patch and 90 grains of 2F Goex.
 
just shows that those old CVA locks actually are/were great with the sear adjustment being made with a screw. You just get a better trigger then when these are adjusted properly. that being said a old school gunsmith showed me how they did it back in the days before cva they used shim stock soft soldered to the tumbler to adjust the amount of engagement between the sear nose and the tumbler works really great but a pain in the a** compared to the cva its what had to be done to my l&r's and t/c's
 
I had a trapdoor that some moron in past years ground down the full cock notch in the tumbler for a better pull. The result was you HAD to YANK the trigger hard to clear the other notches defeating the purpose of lessening the trigger pull!
 
Pretty sure TC used the same tumbler for both the single and set trigger versions, as the locks were the same. The difference was in with the triggers. My point was that the process of reducing the full cock notch depth essentially removed the case hardening and the steel supporting the notch, while changing the geometry of the lock’s functional components. Basically shade tree gunsmithing that works until it doesn’t.

One thing I’ve done to reduce trigger pull on the single trigger TCs was to replace the sear spring with one made with smaller diameter spring wire while keeping the free length of the spring the same.
The sear lift will reduce both trigger pull weight and creep without reducing either main spring weight or trigger return and or sear spring weight.
Creep effects my ability to acquire the best accuracy available more than any reasonable trigger pull weight up to about 5 lbs.
With my old beat up, work hardened fingers I can't even feel a trigger of less than one pound any more. Set triggers of ounces are useless to me now. I like and need a crisp, creep free trigger of about 1.5 to 3 lbs now days for my best off hand rifle and pistol shooting.
I still have pretty good non-corrected vision at 74 years but am using reading glasses more now days for close up stuff and noticing not being able to see in the dark quite as well.
This getting old stuff really isn't for sissy's is it!
 
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I had a trapdoor that some moron in past years ground down the full cock notch in the tumbler for a better pull. The result was you HAD to YANK the trigger hard to clear the other notches defeating the purpose of lessening the trigger pull!
The lock in my photos is a TD lock but the only lock I had pictures of available with the same basic features as most muzzle loaders use to show the modification.
 
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MY guess is that mod will work for a long time on any gun not used a great deal like a competition arm would be before showing stress. Time and use are what shows up any weakness in original design or those caused by us gun mechanics.
I've on occasion had to repair/replace my own ideas of design improvements over the years.
I've had two pistols take off on me with shortened full cock notches and lightened springs.
You can tell when a magazine load of spent cartridges are all still hanging in the air at the same time , your jaw drops open and your eyes bug out ! 😄
The Brrrrrrrrrrrrrrrraap noise of full auto and a "What the Hell" exclamation says it all ! 😄
 
Next time I have the Walker apart I'll try to remember to post a picture of how to configure a sear lift on a revolver hammer. I usually just nick the front of the full cock edge when drilling the lift purchase hole to make sure the trigger nose/sear will not trip on any gap left between the lift and full cock notch and then show how it needs to be tapered off at the rear so the trigger can cam up the angle to the reduced contact engagement.
Here is the promised photo of the sear lift on the new Walker. Note where the carbide center drill just kisses the full cock notch to insure no gap for the trigger sear to catch on.
Also note the radius formed on the back side of the lift to smoothly cam up ( transition) the trigger sear nose to the reduced engagement of the full cock notch thus reducing trigger pull weight and creep safely without screwing up swing radius geometry that catches or bangs up the half cock notch and trigger sear nose.
This modification is one of the best I have ever used to advance ones accuracy as a function of trigger control on hand gun as well a rifle !
 

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