How to fix trigger slap?

[yahoody]

Riddle me this? I have had two SAA that after a nice trigger job give some nasty feeling trigger slap. Actually twangs the trigger finger when dry firing with snap caps. Out of dozens of SAA guns only had two do it. These 2 guns (like most I own) have a standard flat leaf spring (trigger and bolt) cut down on both sides, have not touched the hammer hooks, a cut down/shaved Wolfe or Colt main spring is all that is done on these two.

Why is there the annoying amount of trigger snap back on these two particular guns?
No real idea what causes it. But would like to hear opinions on why it happens and how to fix it.

thanks much!

[St. George]

Doesn't sound like your 'gunsmith' knew what he was doing, because you sure as hell don't do action work like that, and shaving both sides of the sear and bolt spring isn't how it's done.

All parts need to be properly mated in order to function together.

The TRIGGER SIDE of the spring is 'gradually' tapered from the trigger to the screw hole - narrower towards the trigger.

Your hammer notches are damaged, and are catching the trigger's nose, or perhaps the sear's bent and not clearing - catching the notches..

Throwing in a new set of springs and some grease doesn't make a 'trigger job' or an 'action job' on a Colt.

You can do that with a Ruger for the most part, but the leaf-springs used require some time and patience to get 'right'.

Kuhnhausen's book will walk you through the process.

Good Luck!

Scouts Out!

[Blair]

I don't know what the term "trigger slap" means.
Can you explain what is happening?
My best,
Blair

[yahoody]

Can you explain what is happening?

Sure, best as I can describe it is the trigger is snapping back into position after releasing the sear.  On the verge of being painful to your trigger finger.  Annoying at best.  Only ever had two guns do it.  Both newer USFA guns.  (key to the problem btw)

Upside was I found the culprit.  Seems a few of the USFA trigger/bolt springs were pretty stout.  Once that was replaced problem solved.

[August]

I'm with St. George on this.  Sounds like the sear (business end of trigger) is hitting the half cock notch as the hammer falls.

Suggest you send the guns to Bob James forthwith.

[Blair]

yahoody,

On these two revolvers, does the trigger move quit far forward compared to your other similar arms? "Almost" pinching your finger against the front inside of the trigger bow?

If this is the case, it is usually caused by the trigger sear being shortened, broken or otherwise damaged.
You can use one of you revolver that does not do this and compare the length of the trigger sear with one of the revolvers that has the problem.
I am thinking you may need to replace the triggers on these two firearms.
My best,
Blair

[yahoody]

Triggers are new, full length.  As I said..just a spring. But thanks for the suggestions.

[rifle]

Excuse me fer sayin so......NOT JUST A SPRING nor the trigger hittin the half cock notch. If the trigger hits the half cock it goes back away from the finger or stops in the notch and it's not possible to be "just a spring" since something has to move the trigger away from the finger so the trigger can slap back to the finger. A stiff spring just makes the slap stronger but doesn't cause the slap.

Sounds to me like the hammers full cock has too much negative engagement put to it to give the feel of a light trigger. The trigger once started takes off ahead of the finger because the mainspring and the hammer are applying pressure and  squirting the trigger out. You know...... like the trigger is moving on it's own without the finger pushin it.. Like once started the mainspring moves the trigger regardless of the finger so the trigger gets ahead of the finger and then hits the overly stiff trigger spring to bounce the trigger forward into the finger that ain't on the trigger then.

Bad. Very bad. Trigger takin off on it's own leavin the finger in the dust. HAIR TRIGGER TIME.  Also probably will need a new hammer or welded and fit again hammer.  You can't put too much negative angle to a hammers full cock notch without inviting trouble. There shouldn't be any negative engagement to the hammers notch.......... Unless the gunsmith knows the only safe place to put it and what amount to put to it. Never put negative engagement to the whole surface of the full cock notch on the hammer. Never ever.

You can (or I can and do) put a negative angle to the full cock notch but "not the area at the back of the notch where the trigger stops in the crook of the notch". That part of the surface of the notch stays as it was "if the angle to the trigger and hammer is right". Right is a little bit of positive engagement angle to it and what isn't negative angled is what the hammer needs to fully  support the width or thickness of the trigger if that is proper to begin with. That way there is a little creep for safety sake since it's impossible to remove all creep because that would remove the whole full cock notch or put a negative angle to the whole thing so it feels like there's no creep because the hammer/mainspring (not the finger)moves the trigger once the trigger is started.
What I do  it's like there is negative angle to the full cock notch only so far back to where the positive engagement begins so there is enough left to let the trigger clear the half cock notch edge when the hammer falls. What's left is a proper angle step for the trigger to rest on that is the width of a normal thick trigger end for safety sake and hardly any creep. If the trigger is pulled normally (as in not painstakingly slow like a target shooter does) there is no real felt creep. No safety concern and a crisp trigger break.

Looking at the hammers full cock notch there will be a line....a line across the notch between the negative angled part and the positive angled part closest to the crook in the notch. The line need be perfectly perpendicular to the sides of the hammer so the whole trigger tip hits the end and lets go at the same time. Not lets go on one side then the other. The line between the negative and positive engagement on the hammers full cock notch has to be clear,straight and crisp.  The negative engaged part on the notch angled enough so once the trigger hits that part it squirts off the hammer by itself making it feel like the hammers creep is not there and feeling like the trigger has already gone off the hammers notch.

Most single actions done that way don't really need much at all taken from the mainspring or the trigger/bolt spring to set a decent pound weight trigger pull. Depends on what that is to begin with. Makes a trigger that breaks like a small glass rod snapped in two. Beautiful feeling.

Anywhoooo.....a nice trigger job done by hand is a work of art in form and function. Makes fer nicer groups too on the targets. NO slap to the finger either with proper angles to each part of the full cock notch.
In my opinion there should always be some positive engagement to the fit of the trigger and the surface of the full cock notch.

I use a trigger hammer jig I make where as the hammer and trigger are mounted on it exactly like they would be in the gun so I can "SEE" what I'm doing and what the engagement is to begin with and to end with.

Anywhoooo....that explains where hammer slap must come from and how to get rid of it and have a safe trigger pull.......I thunk. Never heard of that kinda trigger slap before this. I thunk I figgered it out.

I'd have the gun checked out since lighter springs could make the trigger pull more unsafe. I guess I riddled that one......fer safety sake. The guns didn't have nice trigger jobs I imagine they are unsafe.

[Pettifogger]

There are only TWO pieces to a SSA trigger mechanism.  The trigger and the hammer.  The only way you can get trigger slap is if something is hitting it.  The only other part in the system is the hammer so that is what has to be hitting the trigger.  Sounds like a bad action job.  Like Rifle suggests the trigger is most likely being hit by the half cock notch.  Did the "smith" put in a trigger over travel screw?  If so, it is possible it is adjusted to tight.

[rifle]

Being fair and all I thunked about the trigger hittin the half cock notch of the hammer kicking it back on the end the finger is at and moving it away from the finger so the stout trigger spring can slap it back at the finger. Very possible. 

Matter of fact..... I've had to do a fix on revolvers with that very same problem in the past but didn't notice the "slap" as such. Just deserning an ungly little sound and feeling. I know that feeling and sound and usually find a trigger with a broken off tip causing it. Sometimes a worn or shortened full cock notch edge. Sometimes a trigger job done that put too much negative engagement to the full cock notch surface.

It's possible to get rid of it at times by rounding the edge of the half cock notch and smoothing it so the trigger doesn't hit it but slids over and around it without being noticed it ever touched it.

When the trigger hits the edge of the half cock notch and bounces around it that is very noticable.

Anywhoooo...changing the stout trigger spring out for a weaker spring is minimizing the symptom and not really fixing the cause.

[yahoody]

Couple of thoughts.  SAA ignition system consists of four parts that work in unison or should, trigger (which is actually the sear),  the hammer, main spring and sear/bolt spring.

Sear on a new USFA part (don't have a set of Colt parts handy enough) is .030"+/-.  But that # gets cut down anyway.  Hammer hooks on a new hammer I have here are .029/.030".  (Colt hammers run .030 to .040" by spec.)   Spring can be anything from stout flat springs to wimpy piano wire depending on what you like.   Never seen this on a Colt for sure.  But the internal radius is the same or should be I believe @ 48.5 degrees.  (this turned out to be the key)


Assuming trigger and hammer contour is correctly mated/matching (on this gun my guess would be this tolerance/clearance is simply too tight)  keeping the trigger from coming back to the fired position just a millisecond later with a lighter spring might-change the feel of the gun.

I'm only guessing.  But do know the lighter weight trigger/bolt spring eliminated much of the "slap".  But still 5% of it I could feel if I was dry firing the gun.  Not much but the problem was not totally solved just as Rifle suspected and others have also noted, it likely didn't eliminate the problem.

So a few moments ago (between paragraphs actually) I tore the gun apart again.  Now I went looking for contact on the back of the trigger and the curve of the hammer under the hammer hook/sear engagement.  No obvious contact there.  So I then checked the hammer and sear mating radius.  Bingo!  Back of the trigger contour was not cut with enough clearance behind the screw hole.  Obvious when I pulled out some new Colt triggers and a few more new USFA triggers.  Easy to fix.  5 minutes may be.  Easy enough to miss if you were building the gun from scratch and a parts bin.

As I said. only ever felt two guns do it.  Both USFA.  Now I'd guess they both simply had out of spec triggers installed.

My thanks to Rifle who admitted he had not seen such a thing and  then proceeded to think it all through anyway... and still came away puzzled   Your comments were much appreciated.  Nice bit of critical thinking on your part.  Thanks for writing it all down.  Got me to rethink it all as well.  Took me longer to type this than fix the gun      

[rifle]

Yahoody, you the man. Found the problem. Commendable endeavor. Yer a Gentleman and a Scholar.


Problem with my thunkin was I had a hard time imagining what "trigger slap" was. Finally realized I had seen that type of thing and remedied it with some guns. Now...goin further into the twilight zone the actual problem with yer gun was one I had remedied multiple times fittin a trigger from one brand to another brand to get a longer trigger or whatever. The back of the trigger does ride the hammer and needs to be compatable with it.

Ifin you ever run across one of these well hidden anomalies again I'd recommend to get out yer machinists lay out dye and paint a thin coat to the parts to see where they are contacting. The dye rubbin off somewhere can make you look at that area closer like gives a clue.

Anywhooooooo........after all this thunkin and typin I need some R&R(rest and relaxation) so......I'm just goin out in the woods and fields with my hound dog as long today as I can. Till dark not comin home till supper is on the table. I'm emotionally damaged from all this thunkin.

I'm glad you fixed yer gun and.....will try to put the fix in my box of tricks in the attic(worn out brain) so I remember it.  I know that stuff but made a critical error. Looked (thunked about) at everything but the trigger. Dumb. Dumb. Gettin old and brain weary I might be.

So... the lack of clearance behind the trigger let the trigger be hittin something like the half cock or some such thing?  Bet it feels good to work the action and not feel that glitch anymore.

[yahoody]

" I'd recommend to get out yer machinists lay out dye and paint a thin coat "

Yep, kinda funny really,  Hundred of guns and only ever seen this but twice.  My go to with crappy parts is generally just grab a new part.  New gun, new parts and on first inspection just flatly missed it.  And the "problem" wasn't enough to keep me from shooting this gun.  Gun spent the last few months at the engraver so hadn't shot it for a while.  But didn't remember this gun having any issues.  Once noticed it was hard to ignore.  Dykem was the next step.  But once I thought where to look the problem was glaringly obvious.

I aspire every trigger to , "break like a small glass rod snapped in two. Beautiful feeling."   When they don't they get rebuilt.  This one was close to that, just not quite right.  Now it acts the way it should.  And no back talk!   Appreciate your encouragement to look at it again.