Spring on the trigger

[Kifsif]

I'm interested air pistol. But the question seems to be a bit more general.

Picture: http://radikal.ru/big/uiwkhssmiiyp7
This is an excerpt from a Russian book written by a prominent coach.
The book was published in 1975 and is dedicated to rifle and pistol shooting. Nothing is mentioned about air guns. So, this is an old book.

Anyway, pardon for the Russian text, but, please, pay attention to the pictures only.

The author suggests attaching a shaped spring to the trigger.
It :
1) Allows executing the trigger pull more smoothly and steadily.
2) Improves the stability of the shooter's body.
3) Let the shooter achieve a quicker and better result.

Then the author writes that highly skilled shooters can use this equipment both in their training process and during the competitions. And then half the page about how good this spring is for the shooter.

And how to attach the spring to rifles and pistols.

We can conclude that this method may be used for a free pistol or a rifle where trigger weight is arbitrary. And as for me, it may be worth trying for air pistol where trigger pull is 500 gr.

Well, anyway, this is interesting technique. I will give it a try during my training process (later, when I make it).
But I decided to consult the rules as to whether it is allowed at competitions.

Ref.: Pistol rules
http://www.issf-sports.org/documents/ru ... nt-ENG.pdf

Page 377.

8.4.2. The weight of the trigger pull must be measured, with the test weight suspended near the middle of the trigger (see illustrations) and the barrel held vertically.

8.4.2.1 A weight with a metal or rubber knife-edge must be used. A roller on the trigger weight is not permitted.

By the way, I have not found anywhere the rule that a trigger should be semi-circular. So, if I'm not mistaken, the trigger shape is stipulated nowhere. So, we can use a needle instead of the trigger. And let the equipment control officials find that middle of the trigger pull. Not a very productive position, as it may lead to conflicts with the officials, which will definitely not profitable.

Let's return to that spring on the trigger. The spring may disfigure the shape of the trigger. The knife-edge of the weight may will find its stable position somewhere on the spring. I mean that this position will hardly be close to the geometric midpoint of the trigger. It may astonish the control officials.

Well, once more: this is an old book.

The questions:
1. Can this spring be useful for modern air pistol shooters or it is absolutely garbage nowadays? If it is not garbage, why nobody uses it in Olympic games?

2. Is it really in full conformance with the ISSF rules? What if it astonishes the officials? What if the weight will just slip off the trigger during the trigger weight control? Can I help that knife-edge find its position by making a small curved slot (this is will be organized as a separate question on this forum).

[Gwhite]

I suspect it may have been a way to implement a rolling trigger when they weren't common. You could add the spring to a breaking trigger, and as you pulled rearward on the spring, the pressure on the trigger would build up as your finger moved to the rear. When the spring pressure exceeded the trigger weight threshold, bang.

You could bend a notch in the middle of the spring to keep the officials happy, but if all you want is a rolling trigger release, you'd be better of buying a pistol that can be set up that way. From the discussions on another recent thread, there aren't very many air pistols that qualify. My theory is that it's difficult to design & manufacture a reliable rolling 2nd stage that is really smooth at the force levels required for air pistol.

[Kifsif]

Gwhite, I have MP-46M (also known as IZH-46). And can't afford to change it so far, unfortunately.

This is its trigger mechanism:
http://www.pilkguns.com/tenp/spizh46.htm

I have never known about rolling triggers before. And remember that the author doesn't talk about trigger weight for an air pistol. As far as I can understand, he suggests this spring even for for free pistol shooters and rifle shooters. Their trigger weight is close to zero. And even for them the author suggests the spring.

Well, as for that notch. I wanted to organize it as a separate question, but let it be here.

https://youtu.be/EP5C_3KiPpg?list=PL8BB ... X9TH&t=111

Please, have a look from 1:51. This is the notch, as far as I can understand. The trigger itself seems not a semi-circle. That's why they need the notch.

This notch confuses me a bit. Not far ago the rules changed: that knife-edge for the weigh was introduced and outlawed rollers on trigger weights. Isn't there a relation between these notches and the knife-edges on the weights? The roller will not be able to cling on to the trigger if it is not semi-circular. Could you comment on this?

[David M]

If it worked in 1975, it would be everywhere today.
Also drum brakes were the rage in the 1970's.........

[David Levene]

2. Is it really in full conformance with the ISSF rules? What if it astonishes the officials? What if the weight will just slip off the trigger during the trigger weight control? Can I help that knife-edge find its position by making a small curved slot (this is will be organized as a separate question on this forum).

You know that, at Equipment Control, the trigger will be required to lift a weight with a knife edge suspended near the middle.

It is your responsibility to ensure that your gun is suitable to be tested in that way.

Cutting a notch near the middle of the trigger to give the edge somewhere to sit is perfectly acceptable. I would suggest however that most EC staff are not idiots. Don't try to gain an advantage by cutting the notch closer to the pivot point in an attempt to gain an advantage. If the EC Officer does not think that the notch is near enough to the middle of the trigger then they will ignore it.

[Spencer]

2. Is it really in full conformance with the ISSF rules? What if it astonishes the officials? What if the weight will just slip off the trigger during the trigger weight control? Can I help that knife-edge find its position by making a small curved slot (this is will be organized as a separate question on this forum).

You know that, at Equipment Control, the trigger will be required to lift a weight with a knife edge suspended near the middle.

It is your responsibility to ensure that your gun is suitable to be tested in that way.

Cutting a notch near the middle of the trigger to give the edge somewhere to sit is perfectly acceptable. I would suggest however that most EC staff are not idiots. Don't try to gain an advantage by cutting the notch closer to the pivot point in an attempt to gain an advantage. If the EC Officer does not think that the notch is near enough to the middle of the trigger then they will ignore it.

AND...
...if it can not be checked properly, it can not be 'passed'

[Kifsif]

If it worked in 1975, it would be everywhere today.
Also drum brakes were the rage in the 1970's.........

This also confuses me. This spring as if mortified having never come to life.

But this spring may be helpful. Why not try: it is simple. If it works for you, use it if it is perfectly legal.
If it is garbage, you will see it when counting scores.

[TenMetrePeter]

I don't see how isolating trigger finger from any tactile feedback can possibly help. So much for crisp break.

[Kifsif]

I don't see how isolating trigger finger from any tactile feedback can possibly help. So much for crisp break.

According to the author it absorbs jerks.

Do you really need any feedback? My coach used to tell me: the shot should be unexpected.

[Kifsif]

I would like to find a clarification by ISSF about that notch on the trigger.
There is this guide:
http://www.britishpistolclub.org/ISSF/T ... judges.pdf

Clause 3.5.
""""
It is the shooters responsibility to present a pistol that is capable of being
tested for trigger weight.
There have been pistols incorporating trigger design, which made the
testing difficult, if not impossible. At its simplest, if the trigger cannot be
tested Equipment Control cannot approve it!
The most commonly encountered problems is triggers angled and/or
curved such that the trigger weight cannot be suspended at the position
where the shooter would place the trigger finger in normal use of the
pistol when the barrel is vertical. In some cases this may be deliberate.
""""
Not very clarifying. Nothing about the notch. Could you help me find such clarification?

[Spencer]

I would like to find a clarification by ISSF about that notch on the trigger.
There is this guide:
http://www.britishpistolclub.org/ISSF/T ... judges.pdf

Clause 3.5.
""""
It is the shooters responsibility to present a pistol that is capable of being
tested for trigger weight.
There have been pistols incorporating trigger design, which made the
testing difficult, if not impossible. At its simplest, if the trigger cannot be
tested Equipment Control cannot approve it!
The most commonly encountered problems is triggers angled and/or
curved such that the trigger weight cannot be suspended at the position
where the shooter would place the trigger finger in normal use of the
pistol when the barrel is vertical. In some cases this may be deliberate.
""""
Not very clarifying. Nothing about the notch. Could you help me find such clarification?

not really necessary to have it clarified - everybody (except some coaches and some manufacturers) seems to understand the intent.

[Kifsif]

I would like to find a clarification by ISSF about that notch on the trigger.
not really necessary to have it clarified - everybody (except some coaches and some manufacturers) seems to understand the intent.

It depends. If you see such notches every day, this may be obvious. If you have just noticed it (like me), then you would like a bit more information.

ISSF clarifies many things. I remember reading something on safety flags for example. And here is the trigger. A very delicate part. Can't it be clarified? I would say it may or it may not. But why not?

[David Levene]

Not very clarifying. Nothing about the notch. Could you help me find such clarification?

There is no reason why any clarification should be written anywhere.

There is no requirement for a notch. All that is required is that your gun should be capable of passing the test laid down in the rules. How you achieve that is down to you.

Many shooters and manufacturers find that the easiest way is to provide a groove/notch for the trigger weight edge to sit in.

[Gwhite]

While not required, I think the popularity of the notch is due to the consistency it provides. With all sorts of trigger shapes & angles, it can be difficult to get the knife edge to sit in the exact middle of the trigger, and a small change in what an official considers "the middle" could result in a disqualification. With the notch, the shooter & the officials should be able to produce identical results consistently.

I have some older pistols that lack the notch, and an old weight set with the roller. This combination a big problem with the common pivoting trigger mechanism. Even with a curved trigger, as the trigger moves, the angle changes, and the roller tends to creep down the trigger. That increases the lever arm, and can fire the pistol at a lower weight than if the roller stayed in the middle. The only way to keep the roller in the middle is to tilt the pistol, which adds an additional uncontrolled variable. If you've ever wrestled with this, you quickly understand why they changed away from the roller. The notch started being added by the pistol makers not long after the switch to the knife edge.

[Kifsif]

If you've ever wrestled with this, you quickly understand why they changed away from the roller.

Don't you adjust the trigger with some margin of safety? I use a weight of 550 gr.

[rmca]

Don't you adjust the trigger with some margin of safety? I use a weight of 550 gr.

No, a lot of people want it as close as possible to the minimum.
But even with a trigger on the 550g mark, depending on the pistol and how far the test weight is from the middle, you might not pass...
Hence the notch to guarantee a equal measurement every time.

Hope this helps

[Gwhite]

If you've ever wrestled with this, you quickly understand why they changed away from the roller.

Don't you adjust the trigger with some margin of safety? I use a weight of 550 gr.

I've had instances where the roller runs off the bottom of the trigger if you hold the barrel vertically. That's with a curved trigger with no notch.