LP10 trigger

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JimJ
Posts: 14
Joined: Tue Sep 07, 2004 11:00 pm

LP10 trigger

Post by JimJ »

I have just recently started looking in to shooting a quality air pistol. One of the forums I stumbled across had a guy talking about having problems setting the second stage of the trigger on his LP 10 to the same low level he had been using on his LP 1. He said he actually had to modify one of the springs, and recommended not trying it yourslef. I wonder if this is a common occourance with LP 10s. They seem to be a very popular choice, but if you can't get the trigger set up right, it kind of defeats the purpose of a dual stage trigger.

PS. I would just go and ask him about it, but I haven't been able to find that forum again recently, and this looked like an active place to get information

Thanks --- JimJ
Walter Young
Posts: 39
Joined: Mon Mar 01, 2004 4:05 pm

Post by Walter Young »

From what I hear, the current thinking of the optimum setup of a 2 stage trigger is that more of the weight is adjusted to be in the second stage rather than the first. The reason being, that it instills the important fundamentals of using a consistant and constant pressure to release the shot.
500 grams is a very light trigger and when the second stage is set to be very light there is a tendency to pause at the second stage which can have the negative effects of overholding, flinching and a feeling that the muscles in the fingers are not reacting to the impulses of the brain as fast because of the minute amount of muscle response to activate the trigger.
However, many people do successfully employ that technique, it's just that it's harder to master and may cause the aforementioned problems.
One of the worst habits to get into is constantly adjusting the trigger.
It's possible that the person you mentioned was trying to bond on the negative aspects of being in the circular mode of confusion of being in trigger adjustment hell.
JimJ
Posts: 14
Joined: Tue Sep 07, 2004 11:00 pm

Post by JimJ »

Thanks for the info. If 500 is very light, and this guy was complaing because he couldn't get under 100 consistently, then maybe he didn't need to be going there in the first place. :>)
Walter Young
Posts: 39
Joined: Mon Mar 01, 2004 4:05 pm

Post by Walter Young »

Well, I can also see his need to want to set it up that way if he has been shooting for years with it set that way with a previous version of the same gun.
Mark Briggs
Posts: 583
Joined: Mon Mar 01, 2004 8:35 am
Location: The Frigid North - Ottawa, Canada

Post by Mark Briggs »

I was the original poster from way back when...

I had been shooting my LP1's for quite some time and had grown quite accustomed to their triggers which are set to something like 450 grams on the 1st stage and between 50 and 100 grams on the second stage. From the factory my LP10 wouldn't go much below 250 grams on the 2nd stage, and also didn't have a particularly "crisp" feeling.

Luckily, my coach and mentor is a shooter who's had the chance to shoot in a few world cups, commonwealth games, etc and has had the benefit of having his LP10 worked over by the Steyr factory technician who attends these events. That technician actually uses a small torch to heat the second stage spring and compress it, making it shorter. The end result is an LP10 trigger which feels much better and will go much lighter on the second stage. I accomplished the same thing (well, almost the same thing) but cutting 0.080" off the spring. I'm now down to less than 100 grams on the second stage, and the feeling is much better.

The reason for the difference between LP1 and LP10 triggers isn't easy to see until you completely disassemble the pistol. The trigger parts are identical in both guns and completely interchangeable. The breach bolt of the LP10 is much larger in diameter than that of the LP1 - this is required in order to be able to accommodate the recoil absorber mechanism in the LP10's breach bolt assembly. In order to accommodate the larger breach bolt, the pockets in which the first and second stage springs rest in the receiver are about 0.080" more shallow than in the LP1. This completely changes the geometry of the trigger. Even though the individual piece parts which make up the trigger mechanism are the same, because they are installed in a slightly different configuration they produce markedly different trigger feel and weight range adjustability.

As for disassembling your LP10 and making this modification yourself, I would still caution against it. I've taken my pistols apart and reassembled them several times without incident, but each time I approach the task with extreme caution. Taking them apart is no problem, save for the one pin in the trigger mechanism which can sometimes be difficult to drift out of its factory-installed position. Putting it back together again is a little tougher to do, requiring you to hold the gun "just so" in order to keep the springs inside as you compress them with the trigger parts and then drift the cross pin back into place. It can be done, but make sure you're home alone with no interruptions, in a very clean area with a hard floor (definitely not carpet - you don't want to drop a spring into carpet!), good lighting and a stable work surface. Get the owner's manual out and study it. Then start disassembling, making frequent reference to the manual to ensure you understand completely how the trigger goes together.

Hope this has helped...


Mark.
JimJ
Posts: 14
Joined: Tue Sep 07, 2004 11:00 pm

Post by JimJ »

Thanks, the info explained things very well. Since there is little or no chance that I will run in to someone to do the work for me, the decision becomes --- is this going to be important enough to me that I should be looking for a different pistol to try. I am just getting started, so I am not already used to the feel of a previous pistol. Luckily I am in no big hurry, so I can be sure to do my research before I make the leap.

thanks again. --- Jim
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RobStubbs
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Location: Herts, England, UK

Post by RobStubbs »

All the advice I've been given is that the 1st and 2nd stage should be roughly equal. That suits me fine and enables a crisp, easy to find end of 1st stage. That also suits my way of shooting (and/or my coaches <g>). It is down to personal preference but for me my LP10 feels great and I would certainly never consider taking the thing apart.

Rob.
JimJ
Posts: 14
Joined: Tue Sep 07, 2004 11:00 pm

Post by JimJ »

I have doing a lot more reading lately, and I have pretty much come to the same conclusion. Especially at my level there is no real reason to try to get a super light second stage, and in fact there seem to be good reasons not to.

Now I just have a question on how you actually go about setting up the trigger. I know when they test to see that the trigger is legal, they just hang a 500 gm weight on it, and if it goes off it is set too light. So setting the overall weight seems easy enough to figure, but how do you go about setting up the weights for the two stages?
Mark Briggs
Posts: 583
Joined: Mon Mar 01, 2004 8:35 am
Location: The Frigid North - Ottawa, Canada

Post by Mark Briggs »

Adjustment of the LP10 trigger is accomplished using 4 screws. Consult your owners manual to determine which screw does what and to familiarize yourself as to the effect of turning each screw.. The heads of these screws are relatively soft so you need to use an appropriately sized screwdriver or risk burring the heads of the screws.

One of the things I've noticed is that there is a large interaction between all the adjustments. Changing one can radically change another automatically. For this reason I would suggest that you do the following:

1) turn 2nd stage weight adjustment screw all the way out (counterclockwise) - note that if you force it you will break it as it is not designed to be removed from outside the pistol, only adjusted from outside. When it stops turning counterclockwise easily, it's as far out as it will go - DO NOT FORCE IT!
2) adjust 1st stage travel to the desired length
3) adjust 1st stage weight
4) adjust 2nd stage weight (note that as mentioned earlier you may not be able to get it as light as you would like it to be - but less than 100 grams is achieveable with patience)
5) adjust overtravel as desired - note that after the trigger releases the sear and the hammer falls, trigger weight decreases substantially. For this reason some people feel it is advantageous to reduce overtravel to a minimum. But beware, if you adjust overtravel to zero, the gun will fail to fire. Some small amount of overtravel is absolutely necessary.

Shoot with the gun like this for a while (100+ shots), then tweak again 'til it feels right, using the order of operations stated above. If you don't shoot lots between adjustments you won't be allowing yourself to become accustomed to the new settings, and you won't allow the settings to stabilize in the gun. If you follow the technique outlined above you should be able to adjust the trigger with a minimum of effort and frustration.

As a side note, to adjust 2nd stage weight, you don't have to take the grip all the way off. Just loosen it until it will rock far enough backward to allow your small screwdriver to access the 2nd stage adjustment screw. This will save you some time.

There was mention made of considering another pistol... I've got to be honest and say that I love my LP10 for its high-tech features which cause the pistol to remain motionless during the shot. But when it comes to trigger performance, the Morini 162 definitely has the sweetest trigger in the business. Now all I need to do is to put the fantastic LP10 trigger shoe on the Morini...

By the way, I like a light second stage on my AP because it much more closely mimmics my free pistol triggers. I find that as I increase 2nd stage weight I lose the cross-training benefit between AP & FP. That's just my preference, and everybody has every right to their own preferences. If you like a heavier 2nd stage and it produces good results for you then you'd be silly to consider changing it.

Mark.
JimJ
Posts: 14
Joined: Tue Sep 07, 2004 11:00 pm

Post by JimJ »

Thanks for the directions. I think I have seen your directions on another thread some place as well. You mention setting the weight on each of the stages. That was kind of what I was wanting to know about. How do you measure these weights. I know you can put a 500 gm weight on the trigger to see if the overall weight is legal, but how do you measure the weights on each stage separately? Thanks ---- Jim
David Levene
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Location: Ruislip, UK

Post by David Levene »

JimJ wrote:I know you can put a 500 gm weight on the trigger to see if the overall weight is legal, but how do you measure the weights on each stage separately?
You really need to use a dial guage with a clamped gun so that you can properly judge when the first stage movement stops.

The big question is, why do you want to know what the 2 stages are. Just adjust it so that you are happy with the feel of the trigger. The individual stage weights are purely academic. I can guess what mine are but can see know point in finding out for sure.
JimJ
Posts: 14
Joined: Tue Sep 07, 2004 11:00 pm

Post by JimJ »

Thanks Mark for all the good information.

While you are feeling helpful, I thought I would pick your brain a little more. Yes, the Morini is one of the others I was considering. I have also heard good things about the trigger on the Pardini. One thing that the LP 10 has that these two don't seem to, is a wide range of adjusments to the grip. It would seem to me that this would make fitting the pistol to me easier, and would require less actual work on the wood. So that would be a plus.

One thing I wonder about. As you are changing the angles of the pistol in the grip, the center line of the bore is no longer sitting the same way it was originally. I have always heard that all gripping and trigger pull pressure should be in line with the bore of the pistol. Does this change once you have twisted the pistol in the grip? I would think you still need to keep all the pressures in the same direction, but it is hard to picture how this would work. Thanks again --- Jim
JimJ
Posts: 14
Joined: Tue Sep 07, 2004 11:00 pm

Post by JimJ »

Thanks for you comment David. I guess you are probably right, the numbers don't really matter. I have just seen so many posts quoting exact figures, that I thought it was common practice.
Mark Briggs
Posts: 583
Joined: Mon Mar 01, 2004 8:35 am
Location: The Frigid North - Ottawa, Canada

Post by Mark Briggs »

Jim - I'll try to answer as best I can here, but please accept the fact that I'm not an expert.

Grip angle is normally adjusted in order to produce the correct sight picture when you raise the pistol. This is often referred to as NPA, natural point of aim. As an example, my Morini 162 would always come up with the front sight away off to the left of where it should be. The only way for me to get the proper sight picture was to use a lot of muscle control to rotate my wrist to the right (clockwise when viewed from above the pistol, looking downward). The amount of muscle control that was required was significant enough that I produced groups with lots of lateral dispersion. The fix for this was to put lots of filler in the grip at the point where the base of my thumb (the meaty part, kinda like the meaty part on a chicken drumstick) contacts the grip. Voila, now the pistol comes up with the front sight centred in the rear sight!

With respect to your question about trigger alignment, I think the statement you've made may in fact be somewhat of an oversimplification. If you look at the technique of pulling the trigger, it would indeed be ideal to have the trigger motion parallel to the boreline. BUT, what seems to be a more accurate description of trigger motion is thus...

"Trigger motion should be parallel to the line of supporting/stabilizing force which is imparted to the pistol by the shooters hand."

In the case of our style of pistol shooting, we are supporting the pistol essentially between the first knuckle of the middle finger and the base of the thumb where it forms the web between thumb and forefinger. If you apply trigger force parallel the the force supporting the pistol you will not produce a lateral force vector to disturb the balance between the mass of the pistol and the muscle force supporting it. If you are applying a trigger force which is not parallel to the gripping force then you must either alter your gripping force to compensate or suffer lateral dispersion in your shots.

That's a long way of saying that altering the grip angle, particularly in the axis of rotation perpendicular to the boreline, should be met with a corresponding change in trigger angle. The only real hitch is that we may alter the position and angle of our trigger shoe, but very, very few pistols will allow us to rotate the entire trigger mechanism with the grip. So no matter how much we want to keep trigger forces parallel to the gripping force, the fact that our triggers pivot on fixed shafts which are mounted perpendicular to the bore means that we are limited in our ability to match grip angle changes to trigger angle changes.

All this having been said (Geez, ain't I long-winded?!?!?), the bottom line is that you should alter the grip angle so the pistol comes up at your NPA. The points lost to trigger movement not being perfectly aligned will be nothing compared to the points you'll lose if the gun doesn't come up in your NPA.

As for weighing your trigger, the point made earlier was pretty much bang-on. Adjust it until it feels right and weigh it to make sure it's match-legal. At one time I had two LP1's and an LP10, as well as a 162EI, so I was attempting to make all three as close to being the same as possible. I accomplished this by placing my 500gram trigger weight on my digital weigh scale. I would then lift the weight with my pistol, much the same as if I were doing the trigger pass/fail test. I could feel where the first stage stopped and would note the weight displayed on the digital scale. I would then adjust the other two pistols for a similar 1st stage weight. Then I would add weight to my 500 gram trigger weight (taking it up to about 600 grams) and be able to weigh the ultimate trigger break point by noting the weight displayed on the digital scale whenthe trigger fired. Of course, this would be followed up by lots of twiddling to make sure the other two pistols were producing similar results. This process took a long, long time to complete as several attempts were required before being able to reliably establish both the 1st stage weight and the ultimate letoff point.

Adjusting the Morini was a completely different game because the trigger feels so different. If I were to adjust it to the same settings as the Steyrs I'd be having unintentional discharges like crazy. Even at 520+ grams it doesn't feel legal... It's sitting at about 400 grams on the first stage and something over 120 grams on the second stage, and still feels lighter than the LP10.


Mark.
JimJ
Posts: 14
Joined: Tue Sep 07, 2004 11:00 pm

Post by JimJ »

Thanks for getting back to me. You may not be an expert, but you definitely know more than I do, and you really have a knack for being able to explain things well. The idea of keeping all the forces you are applying to the pistol in the same direction makes a lot of sense.

Thanks again --- Jim
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