TargetTalk

I'm a decent but not great shot (505-520 in .22/.32 ISSF 600) and trying to get better. Recently I've become intrigued by overtravel and plan to experiment with it, but wanted to pick some brains here, too. I'm trying to figure out how much overtravel is desirable. My theory is that the shot is often thrown during the short period when the trigger breaks and the shot is still not gone, or if the trigger comes to an abrupt stop after the overtravel. My feeling is that some overtravel is desirable, both mentally (by consciously not letting the trigger reach its stop after it breaks, to help avoid snatching at the shot -- what I call a "now!"), and physically (disturbing sight alignment through the trigger hitting its stop before the shot has left the barrel). On the other hand, too much overtravel may cause other problems. Thoughts?

I did try a search on overtravel here but didn't come up with any threads on this topic, so I apologize if it's been covered before.

Yep, Ed, it's been covered here before- but I'm sure plenty of us will talk about it again!

You are correct that a fundamental design deficiency of mechanical triggers is the sharp break from "X" grams to "Almost Zero" grams as the trigger passes throguh the sear release point.

Theoretically, you would like zero creep before, no movement during, and no avertravel at all after sear release. With a constant pressure before and after, and a clean "step" in the middle.

(Some service pistol champions actually reduce the overtravel to a "negative" number, so that you are physically compressing the trigger mechanism itself for the last couple of ounces of trigger force.)

But "theoretically" and "preference" are two differenct things. Some folks prefer some "smooth creep" before letoff; with varying degrees of sear engagement geometry to get a distinctive "roll" or "plunger" etc. type feel.

Some folks prefer to have the trigger come through the sear and then just flap around in space for a while before hitting the stop.

Back to the "theoretical" issue, you have to decide what amount of overtravel works for you. While zero overtravel (or as close to zero as mechanically possible) might improve the stability of your grip/wobble during the shot, does it cause you to get chicken finger? Or does it reduce the reliability of the firing mechanism? Does it cause uncomfortable variations in trigger force?

You have to set up your rig to optimize what gives you the best results, given the physical limitations of the design of the system.

HTH

Steve Swartz

Not looking for an argument here, but.... What goes from'"X" grams to "Almost Zero" grams' is the pressure on the back end of the trigger from the sear. It represents at most a very small fraction of the total felt or measured weight on the front end of the trigger. That weight derives from the spring(s) that allow the trigger to lift the prescribed 500, 1000 or whatever grams. The springs also provide the desired balance between 1st and 2nd stages. In a properly designed trigger, the pull weight remains pretty much constant as the trigger is pulled through the sear release point and beyond. Spring selection and the geometry of the levers will alter that by a bit but not much. For instance I believe that the pull weight of the hugely respected CM162ei actually goes up slightly as it reaches the end of its travel - well after the shot has gone.

Okay, catch my breath now. Back to overtravel and how much is "desirable," it's way too subjective for there to be a right answer. Much like the never-ending arguments about what makes a pistol more forgiving than another, it's in the mind of the shooter.

My perception is that my subconscious mind is actually able to do quite a lot of damage to the shot after the sear releases but before the shot has left the barrel. It senses the release of the sear and reacts by a rapid muscle twitch; in a poor shot, of course -- in a good shot everything is focused on keeping still/calm through the entire shot process. I believe this reaction is accentuated when there is minimal overtravel, since the finger/trigger bottom out against the gun on both good and bad shots. My hope is that by increasing the overtravel I can prevent bottoming out on the good shots; a good shot will break with even pressure and no rapid stop of the trigger. A bad shot (snatching at the trigger) will contrast more to provide me with feedback. That's the theory, anyway. God knows, I've been through enough "fix of the week" stuff in this hobby! We'll see.

Say, that's irritating! I can't see any control for overtravel on my Hammerli SP20. You can adjust all kinds of stuff but apparently not overtravel. Anybody know if there's a screw for it?

Steve,

I think you need to try out some mechanical triggers again. I know you do not like them because you all ways seem to poke fun at them and think they are inferior. All triggers have mechnical parts, some just have a few less mechnical parts. None of the ones I shoot go to almost zero. They all stop moving a very, very short distance after the sear releases. This is my preferance.

Ed,

I like to have the trigger stop moving when the shot breaks. Your finger should not be moving very fast and just before the shot breaks you should have taken up most of the trigger weight. When your finger applies the last little bit of pressure the trigger should move a very little. For me my sear and over travel are set up so it is hard to tell if anything moved as the last little bit of pressure is applied.

I have always felt if you have any potential for your finger to move after the sear then you could affect your sight picture. Also as you shoot more you should be able to build up muscle memory where you finger will become use to repeating the same thing over and over and after applying the required force to break the shot off you finger will stop moving or continue to slowing moving to the rear until it stops. My first coach allways tried to stress moving to the rear and not any other direction.

When it comes down to it you need to find what works for you, perfect it and stay with it so it becomes mechnical and you do not have to think about it.

Are we not overlooking the obvious test for determining the setting for overtravel? A couple of contributors have made oblique reference to it. I refer to dry-firing!
If, during dry-firing, the sight alignment (relationship of the front sight to the rear sight) is disturbed as the "shot" breaks (or immediately afterward) and you know you are not "flinching" (anticipating the shot, the mental "now") then look to the overtravel setting and experiment with it until the sight alignment disturbance is eliminated.
It works for me.
Mike T.

The subject is fascinating to me because it is dynamic and subjective.

I asked Erich B about it and his advice was to use a stop on mechanical triggers and none on electronics.

That still didnt explain why. I occaisionally gust into the 570's in air. My Morini has no stop and my Steyr LP1 is currently set without it. My worst scores were with a 45.

I believe that the heavier the trigger, the more a stop is needed. I tried to prove it dryfiring with a RIKA. With a 45 and a lot of overtravel, I got a lurch after the shot every time.

With the stop, there was no lurch. The lighter trigger FP (no stop) and AP with or without stop didnt show the lurch. The force on the gun has to change after the sear releases, therefore an unbalanced force must result in an acceleration. The bigger the change in force, the more lurch.

The trigger stop eliminates that but adds a problem. If your finger has jerk at the time of the sear release, the gun jerks from hitting the stop. If you are smooth, there is no jerk. Therefore, the lack of a stop may make up for poor trigger control up to the limit of the lurch imparted by the sear force change.

my 2 cents; anyone got a better theory?

Bruce:

Thought provoking post as usual. My $0.02 would be that the "jerk" *is* the "lurch."

Jerk/lurch occurs when the force imbalance is present. If you set your trigger stop right on up to the sear release point, you don't have that big dropoff. You do have a potential uptick; but with a typical mechanical you have one or the other.

Good point about the trigger force with Free and Air. The whole constant force/force dropoff does become pretty moot (it doesn't go away; it's just really small) for most shooters an Air Pistol. Definitely with a Free Pistol. The force imbalance created by 500 grams off-centerline can be managed. Some pretty good shooters toss up some pretty good scores with mechanical triggers with no stop (or a stop way behid the release point; same thing).

Not sure about the "secondary slap" as your finger comes back throught eh null onto the stop (when you have a aloppy stop setting). Could certainly jerk your follow through around; but hopefully, round will be away by then.

Steve

I agree with Mr. Mike Taylor, use dry firing and see what happens. Place trigger finger differently, move trigger back or forth and see the result.

As I am shooting a lot of different guns, with or without electricity (no difference to me, if good) over travel has never caused me any trouble.

Go dry fire!

Kent

My original thought was that there are two components at play when I break the shot. One is strictly physical: you are applying a certain amount of pressure on the trigger when it breaks, and that pressure causes the trigger finger to travel rapidly through the overtravel to the stop. The greater the pressure required to break the shot, the faster the finger moves after the shot breaks and the more likely it is to disturb the sight alignment upon impact with the stop. With increased overtravel and a smooth application of pressure, it should be possible to decelerate the finger after the break so that there is no contact with the stop, or very little. This could also relate to the second component, which is mental. Any tendency to snatch/jerk the trigger would be easily felt since contact would be made with the stop. On a smooth application of pressure this wouldn't happen.