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View Full Version : So lets talk about trigger pull in a BP revolver


Doc Hoy
December 7, 2010, 03:24 AM
As I see it there are three aspects of trigger pull

1. Smoothness of the trigger
2. Force required to discharge the pistol
3. Creep.

So here are my questions:

1. Did I miss anything?
2. What are the effects on POI/POA of these different aspects of trigger pull?

Until you respond I am happy to remain...

Your most humble and devoted servant,

napp
December 7, 2010, 10:30 AM
Doc,
I would think that "slack" needs to be included in your list of trigger pull characteristics. The old BRASS acronym will always be embedded in my mind from my Army days.

Breathe
Relax
Aim
Slack
Squeeze

For me, the "point of no return, time to get serious" thought occurs during the instant I take up the slack on a trigger. It is the instant of total commitment to the shot. The amount of trigger slack will, of course, vary from gun to gun. Different people prefer different amounts of slack; but there is no denying it affects the shooter's mindset and the overall "feel" of a trigger.

I'm not sure I can adequately reply to your questions about POA/POI. Instinct is a difficult thing to put into words. Suffice it to say, I can usually tell if a shot is good (or not) when the trigger breaks. Once again, I refer to the Army marksmanship training where we were required to "call our shot."

zippy13
December 7, 2010, 10:32 AM
Doc, by "Force required to discharge the pistol" are you referring to force required to operate the trigger, or the force of the falling hammer that causes the cap to fire? Also, you didn't mention length of the trigger pull.

My experience is limited to associating changes in POI/POA to changes in the pistol's loading (bullet weight and powder charge). Like other members, when I changed to bullet from ball in my Ruger Old Army, my POI shifted upward beyond the adjustment capability of the original sights.

One might assume: If a pistol is modified for a smoother, lighter, shorter trigger pull, then the shooter might sub-consciously employ a slightly different (relaxed or tightened) grip. If the grip is changed, then the pistol's recoil dynamics will change. And, if the recoil dynamics are changed, then the POI will be altered. Is this along the lines of what you're thinking?

Rifleman1776
December 7, 2010, 11:46 AM
Those BP C&B revolvers can have their trigger pull improved through stoning and smoothing of action.
Weight of pull can be adjusted to suit the shooter by stone work on the sear.
Creep and heavy pull will affect accuracy.
However, I would caution, if you adjust your revolver for optimum accuracy on the target range, it should be used only for that purpose. As a hunting or field gun trigger pull should require a heavier pull for safety.

Doc Hoy
December 7, 2010, 12:56 PM
Rifleman,

I agree about the safety issue. I use my pistols only in what most would consider a target shooting situation. So safety is less a consideration at least as it applies to the characteristics of the trigger. I must hasten to add that I have had only one unintentional discharge in my life and that was due to a light trigger and my inattention to what I was doing. I do understand that a pistol that is optimized as you describe requires additional awareness on the part of the shooter.


Zippy,

I should have said force required to pll the trigger so as to discharge the pistol. For length of trigger pull I am using the term creep
and what napp is calling slack. (At least I think these are the same thing although to some, slack might mean only the amount of trigger travel before the sear begins to move and this would include the looseness of fit of the trigger and trigger screw and such.) It is the amount of trigger travel before the sear clears the hammer. By smoothness I mean the characteristic of trigger pull which is improved by smoothing the surace against which the sear bares before the hammer falls.

zippy13
December 7, 2010, 01:44 PM
From napp's Army training, doesn't term "take-up the slack" usually mean the travel required prior to actually moving the sear against the hammer? Typically, this is inherent with semi-auto pistols, where the trigger and sear are linked, usually with an intervening disconnector, instead of the direct trigger-to-hammer contact found in SA revolvers. Any take-up in a SA revolver because of "looseness of fit of the trigger and trigger screw and such" might be called slop instead of slack. YMMV
Weight of pull can be adjusted to suit the shooter by stone work on the sear.
True, but as you also noted, this should be done with caution. To reduce the weight of pull, don't most home-pistol-smiths first go to lighter hammer and trigger return springs? If the operation goes south, changing back to the original springs is a lot easier than trying to "undo" sear changes.

With Doc's considerable experience, none of this is new. I'm curious to learn what he has in mind. Perhaps he has something up his sleeve for his latest project pistol. I've always wanted to ask: What's up, Doc?

napp
December 7, 2010, 01:54 PM
Doc,
My definition of ""'slack" is the initial free movement of the trigger before it begins to activate movement of the sear (some refer to this free motion as "take-up").

I consider "creep" to be the distance the trigger must move (after the slack is taken up) before the sear is actually disengaged. Most of my shooting is punching paper; so I usually prefer as little creep as possible. The exception to this preference is my carry guns. Us older guys had a term to define the lack of creep...it was "hair trigger". I would suppose that is no longer a PC term; and best left unsaid in a court of law.

Doc Hoy
December 7, 2010, 02:00 PM
I am getting bored with Elmer Fudd's lack of skills. So to increase the challenge I am doing a trigger job on his shotgun.

:D

I told you there is no serious side..... :)

No....Actually what I am trying to do is to understand trigger jobs on BP revolvers without actually going to the experts and bothering them. It is the kind of thing I like to work out for myself. If a person is able to make a pistol perform better because he truly understands the operation of the pistol, the hand, the eye and the target as a system and also understands what the expert is trying to acheive, then the person has learned something of which he can truly be proud.

All of this stuff can be understood but as I don't ever shoot with other people, I have no basis for knowing what POI/POA gain can be hoped for. I think I know how it should feel at least I know how I would want it to feel.

I have never even handled a pistol upon which someone has done a quality trigger job. I have one which I suspect some work was done, but as I bought it used from a disinterested party, all I know is how it feels: Smooth pull indicating a lack of rough spots on the bearing surfaces, very little travel, and a light pull in comparison with other newer pistols. I have not inspected the innards with the idea of checking the components for evidence of a trigger job because after a pistol has been shoot a couple hundred times, I doubt much evidence would remain OR the mere action of shooting the pistol has self-performed most of the work that a trigger job would have accomplished.

Perhaps I would have been better advised to ask.... 1) What happens to the muzzle of a pistol between the time the shooter commits to the shot and the time when the pistol discharges? and 2) What part does the mechanical function of the trigger play in that muzzle behavior? I think many folks out there know exactly what happens and can relate it without even thinking about it.

junkman_01
December 7, 2010, 03:03 PM
To me, being an older military vet, "take up the slack' means just that, because all US rifles prior to the M16 had two stage triggers. The first stage was slack. The second stage discharged the rifle. I actually prefer them on my rifles.

kwhi43@kc.rr.com
December 7, 2010, 05:42 PM
I think you missed one very important thing. That is overtravel. That is where
the trigger keeps going back after the hammer is falling. Very bad for accuracy. All my revolvers have a trigger stop in them. When the sear is tripped, the trigger stops.

Doc Hoy
December 7, 2010, 05:46 PM
Hmmmm.

Is that all of your BP pistols? and if so how is it worked out? Shim in the trigger guard?

napp
December 7, 2010, 06:27 PM
Doc,

An overtravel stop can be done with an adjustable set-screw. Either in the trigger...or the trigger guard...an Allen head screw is the most common.

http://www.google.com/url?source=imgres&ct=img&q=http://www.pyramydair.com/blog/images/2300T-overtravel-screw-web.jpg&sa=X&ei=RsH-TN-rII-q8Aavq4D9Bw&ved=0CAQQ8wc4Kw&usg=AFQjCNGl8OZqdNikV58MlmfCCZTCJcykaA

http://www.google.com/url?source=imgres&ct=img&q=http://www.expeditionexchange.com/shooting/sw3%2520010.JPG&sa=X&ei=hcH-TM3XGoT78AaV3fn9Bw&ved=0CAQQ8wc4dQ&usg=AFQjCNHrVP5wPGJrtpp2WMusDaMHANksHA

kwhi43@kc.rr.com
December 7, 2010, 06:45 PM
Right, Mine are in the trigger guard on the inside so as not to be seen.