Trigger creep

[Mike C]

I am building an English rifle with a late Ketland (Chambers) lock. Pull weight is about 3lbs but there is too much creep. What would you lock tuners suggest?
Mike C

[bob in the woods]

In my experience, the point at which the trigger is pinned, and the angle of the engagement with the sear  often has much more to do with creep than the actual lock itself.

[Joe S.]

I'm probably the exception but I like a little travel before it goes off.I like to feel the sear as the hammers about to drop if that makes any sense. Was never a big fan of hair triggers with to light a pull weight.Very curious to what's to much for some vs. just right though and how its handled.

[rich pierce]

Likely a leverage situation. Travel and trigger weight are inversely proportional. More leverage (a longer lever arm) results in longer travel. If you re-pin the trigger with the pin lower toward the trigger plate you will probably get a heavier pull but crisper. Sometimes that feels better, shooting. We are not talking about trigger rattle here, right?  Movement before resistance?

[Bob Roller]

I am building an English rifle with a late Ketland (Chambers) lock. Pull weight is about 3lbs but there is too much creep. What would you lock tuners suggest?
Mike C

The depth of the full cock notch in the tumbler is the problem.
That tumbler should be "File hard" so a diamond coated file
can be used to reduce the height of the full cock notch.
Do NOT alter the angle of this notch as it can create a hazaed.

Bob Roller

[D. Taylor Sapergia]

I agree with Bob... a few licks on the tumbler to reduce the depth of the notch of the full cock position will make an enormous difference in creep.  But go slowly, keep everything square and test often.

[ron w]

it is probably a combination of both conditions mentioned. without actually seeing and handling the rifle it is foolish to say that it is any one specific condition. trigger geometry can make or break a good shooting rifle. it is best to research all you can about the association between trigger and sear before taking for granted any specific remedy. basic rules,.....the farther the pivot pin is away from the sear bar contact point, the less the creep, but the higher the trigger weight. and the closer the pivot pin is to the sear bar contact point, the more the creep, but the lower the trigger weight. you must first establish safe and relatively short sear engagement with the tumbler amd then locate the pivot pin to minimalize change in the travel association between trigger and necessary sear bar travel to break the sear. ideally, the travel of the trigger should very loosely match the travel of the sear bar needed to break the sear. that will be the least travel at the closest to sear pressure obtainable at the trigger. measured at the trigger, lighter than sear pressure means the trigger pivot is closer to the sear bar and higher than sear pressure means the trigger pivot is too far away from the sear bar. there are conditions where you might want the trigger pivot farther away, to reduce trigger creep, but you will always pay for that with higher trigger pressure. if you have good trigger control, slightly higher trigger pressure in relation to sear pressure can be better because although trigger pressure is higher, creep is minimalized and the sear will break crisper. anther consideration is that the travel of the trigger bar is close in radial movement to the sear bar. when the trigger bar  contacts the searbar at higher than parallel angles, the trigger pressure will be increased and the sear bear will have to slide on the trigger par which increases friction that produces higher trigger pressures. that said,...the pivot pin should also be as close to the trigger bar's top, or the surface that contacts the sear bar, as safely and reasonably possible. 

[P.W.Berkuta]

I am building an English rifle with a late Ketland (Chambers) lock. Pull weight is about 3lbs but there is too much creep. What would you lock tuners suggest?
Mike C

To be clear on this -- are you talking of free trigger travel before trigger bar makes contact with the sear arm or are you talking about "creep" after the trigger bar contacts the sear arm?
Ron W has a fine discreption above .

[Joe S.]

Good point,theres trigger creep and trigger slack

[Bob Roller]

Good point,theres trigger creep and trigger slack

High quality English and other Continental guns and rifles have a light
thin spring to keep the trigger release bar in constant contact with the
sear under all conditions.If this spring is broken or missing the trigger
will rattle and have very noticeable slack before it engages the sear.

Bob Roller

[Eric Kettenburg]

All good points - IF we are indeed talking about creep, as opposed to slack i.e. free play before trigger bar takes up contact with sear - the combination of a high trigger pin point, a deep full cock notch and a heavy sear spring will make for a trigger that feels like you are working it though a 3" sponge.  I remember a number of years back there were quite a few articles and posts on fledgeling message boards about pinning the trigger higher, for less 'pull weight' but this does equate to more creep albeit less perceived force required.  To ensure a good trigger pull, you need (1) to ensure that the actual break at the sear/tumbler interaction itself is very snappy and crisp, and that the tumbler notch angle is correct and matches the sear travel angle.  (2) There needs to be a balance in the location of the pin, as if too low it will really stiffen up the perceived pull and if too high, you'll introduce the big a$$ sponge feel as I noted.  (3) Too much strength in the sear spring will actually introduce a microscopic torquing effect in the sear arm as well as the sear screw/hole clearance, which also will manifest in the form of a longer, spongier feel.

A good trigger should feel like a piece of thin glass rod snapping at the actual break point.  This is usually not very hard to obtain in my opinion.  What is much harder is dealing with all of the above mentioned effects that will come *before* that snapping-glass trigger break.  Especially in a flint gun, where you are dealing with a typically hand drilled trigger pin that is simply installed though wood as the carrier (of the pin).  Making a pin that is very slightly tapered will help.

[Joe S.]

Eric,very nice explanation with the glass rod analogy. I quess that's what I was trying to say in my original post.To feel that glass rod bend ever so slightly before it breaks.That's the sweet spot atleast for me.

[Mauser06]

So....Does anyone have a good video or tutorial on obtaining a nice clean trigger?? 


I'd even be interested in properly setting of commercially available triggers.

[Mike C]

Thanks for the replies. There is no slack at all. Like most English rifles, the trigger pin is in a slotted post integral to the trigger plate. It is fairly high and leverage is good. Bob Roller's suggestion to hone a little off the tumbler to reduce the depth of the full cock notch thereby reducing the necessary travel of the sear seems like a good fix. The same affect could be achieved by honing a bit off the top of the sear. A little of each might be the way to go.
Mike C

[smylee grouch]

If you only honed some off the top of the sear, wouldn't your sear go into the full cock notch deeper thus making a longer pull? Or did I read that wrong?

[Eric Kettenburg]

If you only honed some off the top of the sear, wouldn't your sear go into the full cock notch deeper thus making a longer pull? Or did I read that wrong?

It would depend upon how the material was removed.  If evenly across the curved face of the sear (above the nose) then yes, the grouch here is correct.  It would also alter the angle of the sear nose/full cock notch interaction.  This assumes the curved face of the sear and curvature of the tumbler are fairly matched, which is actually not the case at all in many locks both old and new.

If, conversely, you only lightly moved material just from the top edge of the sear nose, assuming that the point of removal was not the primary contact point of the sear/tumbler depth interaction, it would lighten the 'pull' weight and the creep initially however I believe this would be bad practice as over time it would promote premature wear to the nose of the sear as well as the edge of the full cock notch; think of a scraping motion across the honed angle as the squared nose/notch interface cleared and the tumbler began to pivot across the portion of that honed angle.

[snapper]

I just got home from shooting at Oakridge TN long range match.  I was using a rifle that was finished last year and this was its first real match.  The lock is a Roller and I had soldered a piece of brass on the tumbler to reduce the length and weight of the trigger pull.  It is at 3.5 lbs currently and I would like to take it down to 2.5 lbs.

Would you recommend that I file on the tumbler and reduce it, or solder on a thicker piece of brass and work that down to what I would like.

thanks

fleener

[ron w]

If you only honed some off the top of the sear, wouldn't your sear go into the full cock notch deeper thus making a longer pull? Or did I read that wrong?

It would depend upon how the material was removed.  If evenly across the curved face of the sear (above the nose) then yes, the grouch here is correct.  It would also alter the angle of the sear nose/full cock notch interaction.  This assumes the curved face of the sear and curvature of the tumbler are fairly matched, which is actually not the case at all in many locks both old and new.

If, conversely, you only lightly moved material just from the top edge of the sear nose, assuming that the point of removal was not the primary contact point of the sear/tumbler depth interaction, it would lighten the 'pull' weight and the creep initially however I believe this would be bad practice as over time it would promote premature wear to the nose of the sear as well as the edge of the full cock notch; think of a scraping motion across the honed angle as the squared nose/notch interface cleared and the tumbler began to pivot across the portion of that honed angle.

   
   
    because of the design of the design of the sear to tumbler engagement, the sear will always go to the bottom of the notch,....so,...if you don't change the diameter of the tumbler in the area of the notch, you will not change creep. taking material off the sear bar nose  does not prevent the sear from going all the way to the bottom of the sear notch on the tumbler. creep comes from the depth of the sear notch on the tumbler and the associative geometry of sear bar to trigger . not from the length of the nose of the sear bar.

[Dphariss]

I am building an English rifle with a late Ketland (Chambers) lock. Pull weight is about 3lbs but there is too much creep. What would you lock tuners suggest?
Mike C

How close is the trigger pivot pin to the sear contact point on the trigger. If this is less than 1/2" creep is hard to avoid.
While having this distance short can lighten the pull of a poorly set up lock it causes excess trigger travel.
CAREFULLY stone the full cock notch and sear nose to POLISH the surfaces. Don't change the angles. Also breaking the edge at the top of the sear's engagement face with a stone may help. Thought I had a drawing of this somewhere but can't find it.

Dan

[Dphariss]

Thanks for the replies. There is no slack at all. Like most English rifles, the trigger pin is in a slotted post integral to the trigger plate. It is fairly high and leverage is good. Bob Roller's suggestion to hone a little off the tumbler to reduce the depth of the full cock notch thereby reducing the necessary travel of the sear seems like a good fix. The same affect could be achieved by honing a bit off the top of the sear. A little of each might be the way to go.
Mike C

If its really too deep I would tend to shim or pin the tumbler to reduce the engagement. On some locks reducing the notch depth by metal removal can cause problems with the fly or the 1/2 cock on some locks. The depth of the notch need not be more than the face of the sear. Thinning the face of sear other than putting a slight bevel at the top edge is not going the help.
Not much of a drawing but it gives the idea. This can reduce creep and/or the trigger pull.


Dan

[hudson]

I hope this is not too far off topic but thought a reminder might save a bit of extra work. On imports I have run into case hardened triggers and sears. Some times less than .010, stone through this and you know the rest.

[rich pierce]

Good tip, Dan. Still stuff to learn here.