ULE Trigger Tuning

[openboater]

I picked up a ULT at the IAO from a Tech that attended the Tech conference. I wish I could have made it Tuesday.

The nice guys at the AGD booth installed it in my new X valve. I came home and started playing. First I installed the level X from my other mag so I'd know the LX was all OK.

I installed the new X valve w/ULT in a new ULE body and new Y grip and it would not shoot. installed the original on-off and the gun shot. So after getting some advise in the Tech forum, I called AGD and they told me to install more shims. ULT shims are .005 thickness and LX shims are .010.

I installed .020 total in shims and the gun shot well.

This afternoon I installed another shim up to .030 total. Trigger feels great.

I lengthened the sear rod so my firing point had very little pre-travel. I can slip a piece of paper between the rod and the back side of the trigger, but not much more.

Then I removed the trigger and drilled and tap'd for a 6-32 and installed a post travel stop.

After playing with the 6-32 screw I have total travel down to .110 inches (110 thousands) Just under 1/8th inch. You need a little excess space so the gun will shoot every time.

and boy is it sweet. I've run a bunch of balls thru it and no problems so far.
After I get used to it I will try a little more shim.

You can see in the poor quality pic how little traved the trigger stop allows.

more later.

[la690]

totally crazy freakin sweet. i want one.

[WarBUCKs]

When the ULE Trigger is in the store, I will buy one... I am afraid though that I will be on vacation when they come out and be sold out when I get back.. :(

[GatoLoco]

hows the reactivity?

[Kevmaster]

about 1/3 of the orignal reactivity

[openboater]

Yes, my reactivity is less. I would descrbe it as softer, not that snap you used to feel.

I have not broken a ball(double loaded) due to short stroking yet. but I only shoot 6-7 BPS max and I don't fan or walk my trigger.

[Havoc_online]

why is it that no matter what we say ppl feel the need to adjust the trigger rod, lol?

[openboater]

I used to agree that adjusting the trigger rod length was a no-no, but I now believe that ULT changes that. Before with a set length pin, the geometry was correct with a set length rod, but now that the pin is a modifiable length due to the sims, the rod length can also be modifiable.

Just like LX made ULT possible, ULT makes adjustable rod possible.

Try it, you may like it !! if not, just set it back to the original length.

[Havoc_online]

:rolleyes:

[GatoLoco]

so the reactivity ratio is the same, so you still notice the kick back of the trigger, because you are used to a lessend pull? (if you can understand wtp* i mean)

*WTP- What The Platypus

[edweird]

yeah its still noticable... infact you need to keep the reactivity low to get shortest distance between the fire and recharge points of the swing without having your trigger runaway

[Jerhew]

wow i didn't realize you'd be able to get the trigger shorter as well as lighter...
i'd still like to see what Tom thinks of this before i'd mess with the rod length...especially because everyone always made such a big deal about NOT messing with the rod

[Gunga]

Originally posted by openboater
I used to agree that adjusting the trigger rod length was a no-no, but I now believe that ULT changes that. Before with a set length pin, the geometry was correct with a set length rod, but now that the pin is a modifiable length due to the sims, the rod length can also be modifiable.

There have been different length on/off pins for years. They varied in length by .005"...the same thickness as a ULT shim. So nothing has changed there.

Don't mess with your trigger rod. Or at least don't complain about your gun not working right after the length is changed. :p

[Kevmaster]

boater: use the shims toadjust what you did with the trigger rod...it works much better

[AGD]

Muummmmm (rubs hands together) we are going to sell a bunch more replacement bolts!! YEAAAA!!!

AGD

[DiRTyBuNNy]

guess that's a hint from the MASTER...you've been owned..in the checkbook...good night, folks....

[sneakyhacker420]

Originally posted by AGD
Muummmmm (rubs hands together) we are going to sell a bunch more replacement bolts!! YEAAAA!!!

AGD

tom just schooled you :eek:

[Jerhew]

thats all i needed :D

[openboater]

OK Tom, I need to know why.

Since I have a gap between the rod and the trigger before the pull, and a gap between the screw stop and the body after the firing, then why would my bolt wear ??

I can agree that if I had no gap between the rod end and the trigger, then the sear would not be fully reset on the bolt and I would cause wear. But with a gap, I am mearly adjusting the length of the rod to my individual gun.

Like gunga said, on-off pins vary .005, so why not use the screw adjust in the rod to make up the differences in tolerences and trully tune my trigger.

Since my hero's are guy's like Dick Fosbury and Bill Koch and a czech named Dufeck, You will understand why I just don't accept 'because that's the ways it's done' for an answer. And I know you are the kind of guy who won't just give 'because' as an answer.

[QUINCYMASSGUY]

Ditto to openboater's post, what specifically about this kind of sear adjustment would cause this feared bolt wear? I presume if the rod is extended so much that it is always partially depressed by the trigger so the sear can never go fully forward and reset, that the tip of the sear is all that's connecting with the bolt and I presume will start to chip it, but as long as the sear pin is long enough that the trigger can be pulled to the point of firing and just a little behind, it doesn't matter if the rod was shorter right? How would that damage the bolt? I can understand that not being enough to let the gun fire though.

So if not releasing a trigger all the way and shooting damages the bolt.... does shortstroking and chuffing damage a bolt too? Inquiring minds want to know :D... but I think I am leaving my sear alone!

Boater, how walkable is the trigger for you? With the rod at an appropriate length can you do it reliably enough where you don't keep chuffing shots?

[openboater]

I have 2 problems walking a trigger, one is 51 year old arthritis and the other is 40 years of target and trap and skeet shooting have given my finger a mind of it's own, and it just can't do it.

So, no, I can't walk a trigger, but I'm not a good candidate to ask.

[athomas]

The sear will always stop in the same location no matter what the on/off pin length is. The on/off pin length changes where the valve shuts off before the sear is released. This also affects the length of time the on/off is open in the event of a partial trigger release(short stroke).

The trigger rod can be adjusted as long as you don't impede the forward motion of the trigger rod which will affect where the sear stops. If the sear stops prematurely then it won't catch the bolt edge with much metal to metal contact. This will put all the force on the tip of the sear and the edge of the bolt. The edge of the bolt will wear more quickly as a result. Short stroking will also cause this problem but I don't see anyone firing thousands of shots while short stroking their guns on every shot. This phenomenon also occurs more frequently in guns with a shorter on/off pin because the sear catch point and the on/off pin open/close point are closer together allowing the gun to be able to fire again without making sure the sear is fully reset.

To reiterate, yes you can adjust your trigger rod as long as it doesn't make contact with the trigger rod while the trigger is at rest. You can put a trigger stop in as long as the stop point is just past the sear release point so that there is no chance of the bolt rubbing on the top of the sear as the gun fires.

[openboater]

Thank You. Very well put.

[QUINCYMASSGUY]

Got it, thanks AThomas! That's what I figured, and I know the occassional shortstroke wouldn't chip the bolt but just wanted to verify it was the same idea though.

*EDITED ADDITION*
OK, an inquiring mind wants to know.... what are the technical terms for the physics principles that result in the ULE on/off allowing the pull weight to be dropped by 66% and the physics principle that explains why the original pull was 3X more? There's got to be some name for why the larger surface area on one side of the on/off area caused more push onto the smaller surface area on the other side. This is more directed at the people who attended the tech conference. Someone mentioned it was a word that started with "H"? Maybe not? Also, the physics principle or theory that results in the retro effect which is reduced by the ULE trigger. Is the reduction entirely the result of the smaller on/off pin top?

[doubletap]

Openboater,
I have recently added a trigger stop to my ule trigger. I have not adjusted the trigger rod yet. My question is, have you had any problems since you added the trigger stop and adjusted the trigger rod? I am about to adjust the rod but I thought I might get some feed back from you or those who have done it, i.e., approximately how much you have been playing with it, approx paint thru it, how often playing...etc... I am going to play a tourney this weekend and I thought if I could get it tuned in time for the tourney I would play with my Mag. Thanks for any words of wisdom.

[openboater]

playing 1 day, 1 case per weekend. 2 cases last weekend. no problems so far, but I will go home and inspect tonite. don't forget to locktite the stop in the trigger and leave a gap between the rod and the back of the trigger.

[doubletap]

Thanks for the info. It helps to know that it is still working, especially with a lot of posts stating not to adjust your rod. I will tune it tonight.

[SteelSoul]

Whould this same setup work on my RT ??
I dont have the ULT but I would love to try th trigger stop and adjusting the sear rod.
Any Ideas???

[Jack & Coke]

"Don't touch your trigger rod" is just a general warning directed at noobies who have no idea of how the sear relates to the bolt on a mag.

You obviously understand the limits and consequences of adjusting your trigger rod.

Don't be too discouraged by the "sky is falling" crowd... keep an open mind, keep experimenting, and keep us updated... :)

[BlackVCG]

If you can't visualize what is happening with the trigger geometry, fire and release points, etc. you are better of leaving things alone.

It's like messing with the engine on your car. If you pop the hood and start adjusting things, taking them apart and putting them back together and don't know the mechanics of it all, it's going to run like crap once it's back together.

[Jack & Coke]

Originally posted by BlackVCG
If you can't visualize what is happening with the trigger geometry, fire and release points, etc. you are better of leaving things alone.

It's like messing with the engine on your car. If you pop the hood and start adjusting things, taking them apart and putting them back together and don't know the mechanics of it all, it's going to run like crap once it's back together.

Excellent!!!

[openboater]

I just inspected the bolt and found NO WEAR. Probably 10-14 thousand shots.

I know what wear looks like cause I once had a hyperframe that eat bolts.

Remember, leave a gap between rod and trigger before firing, and a gap between trigger stop and grip frame after firing. Start with more gap, and shorten it up as you get more experience with it.

As far as doing this with a RT / Retro, it should work, but because of the increased reactivity, I've left mine stock. The forces are such that I don't notice the increased travel.

[athomas]

Originally posted by QUINCYMASSGUY

OK, an inquiring mind wants to know.... what are the technical terms for the physics principles that result in the ULE on/off allowing the pull weight to be dropped by 66% and the physics principle that explains why the original pull was 3X more?

Is the reduction entirely the result of the smaller on/off pin top?

When the front chamber is fully charged the only pressure on the on/off pin is the pressure exerted on the small section of the on/off pin. This is a mathematical calculation.

(Top area of the pin) minus (bottom area of the pin not included in the stem) equals the pressure area that the air will push on. The resultant area is the small section area of the pin. Since the force is equal to the psi multiplied by the area we get a force in lbs.

The old pin had a larger pin diameter at the bottom. Therefore the force exerted was also larger.

The recharge of the valve is another part of the pin. The recharge force is initially excerted on the top of the pin. The larger area of top of the pin combined with the higher input pressure of the retro valve is the reason we have a reactive trigger. By reducing the area of the top of the pin, we reduce the initial reactive recharge force.