Classic valve on/off pin adjustment

[barkingspider]

First off excuse the ignorance, but I got think about applying the same knowledge and approach in shortening the on/off pin some do with there pneumag. I think the only topic of shortening the RT on/off pin from the standard .750 down to ~.730 for a more reactive valve with trigger pull have all been associated with a xvalve or RTpro valve. For those knowledgable and familiar with the subject, why haven't I heard anyone approaching this with a minimag/classic valve's on/off assembly? Can you shorten the pin length, by gradually filing it down, on a classic valve or minimag valve's on/off pin? Is it possible to use the RT on/off pin as some do in the minimag/classic valve and shorten that assemblies pin, therefore finding a sweet spot with a increased reactive trigger? Again, I'm sorry if this is a dumb question. However, I thought I would ask where I know someone would know the answer, and/or know how to explain if I was lost understanding a simple concept.

[zulubravo44]

First off excuse the ignorance, but I got think about applying the same knowledge and approach in shortening the on/off pin some do with there pneumag. I think the only topic of shortening the RT on/off pin from the standard .750 down to ~.730 for a more reactive valve with trigger pull have all been associated with a xvalve or RTpro valve. For those knowledgable and familiar with the subject, why haven't I heard anyone approaching this with a minimag/classic valve's on/off assembly? Can you shorten the pin length, by gradually filing it down, on a classic valve or minimag valve's on/off pin? Is it possible to use the RT on/off pin as some do in the minimag/classic valve and shorten that assemblies pin, therefore finding a sweet spot with a increased reactive trigger? Again, I'm sorry if this is a dumb question. However, I thought I would ask where I know someone would know the answer, and/or know how to explain if I was lost understanding a simple concept.

I don't know about the technical aspects of this question, but I will say that I picked up an emag RT on/off with a .712 pin and dropped it in a classic valve... didn't fire.

Then I bumped up to a .750 and have had excellent satisfaction. I haven't tried filing it down at all though. If I had a spare rod, I might try it and let you know how it went!

[Menace_AO]

Your question is a good one.

Reactivity is a function of several factors, one of the most important of which (and arguably THE most important) is force differential between the top and bottom of the pin.

The classic valve is a (quasi) pre-regged valve, so the pressure acting on the pin top is the valve's operating pressure of ~ 450-470 psi (in case of L10 bolt).

In the classic valve, this amounts to about 5 lbs top force. The pin is single diameter, so pull force is relatively high. Good luck with reactivity there.

The RT-style valves, on the other hand, are post-regged, so pressure acting on the pin top is whatever the tank is outputting that day. If it is 850 psi you now have about 9.6 lbs acting on the top.

To add to the mix, the pin in the RT has two diameters which create an additional force differential, so that pull force is roughly half that of the single diameter classic on/off.

When the valve recharges, you have a lot of force (close to 10 lbs) acting to push the pin down, and the trigger forward. That, coupled with a lighter trigger pull introduces a meaningful differential, which translates to speed. The greater this differential, the more likely you are to hit a sweet spot and have the RT effect, and the higher the cyclic rate will be. Increasing input pressure increases your effective rt bandwidth AND rt cyclic rate. Shortening the pin increases the rt bandwidth.

Pin length is part of what effectively times the valve (though most people don't think of a mag valve being timed). Effective pin length is inversely proportional to rt bandwidth. Too much effective pin length and the sweet spot will be impossible to find (and may not even exist) and you will move toward starvation. Too little length and the sweet spot will be impossible to avoid and you will move toward runaway.

Shortening the pin decreases the time between sealing off the dump chamber and releasing the sear, which decreases the travel necessary to get things going again, and thus increases the likelihood of finding the 'sweet spot'.

Again, there are several factors at work here, all balanced, all working together, to make the rt effect a reality.

To your purpose, the classic valve recharges more slowly and with less force, making it impossible to recharge as quickly, and nigh impossible to cycle in any remotely 'reactive' way.

The good news, however, is that you can get an RT on/off, slap it in and cut your trigger pull in half.

Get a shorter pin (Tuna sells all manner of lengths) and you can increase responsiveness to a pretty decent degree.

In super ultra rare extreme cases, at least according to legend, if you are impossibly lucky and sacrifice just the right maiden in just the right volcano, you can get a slight bit of reactivity out of the classic in this manner.

But don't count on it.

Even the RT-style valves usually need some help to get trigger bounce.

Classic valves need radical invasive miraculous intervention. :)

It isn't that people haven't tried to improve the classic valve (they have); it's just that you are fighting an uphill battle, when you could simply get an RT-style valve that was built (whether deliberately or incidentally) to run that way.

Hope that helps.

[Cyco-Dude]

i've tested this, but only with .750, .745 and .740 pins. it will not affect "reactivity"; the classic valves just don't do that. i'll have to look for my data, but i seem to recall it not really making much of a difference. up to a point i'm sure it will cease to operate. the main thing is the lighter trigger pull.

[Spider-TW]

add to all of that^^^...

On a single slow pull, a shorter classic on/off pin should break with the same feel as a longer one. The main difference will be felt when rapid firing. With a shorter pin, your finger won't have to pull as far against the on/off, or let off as far for a recharge which would help with chuffing. It's still easier to trim an RT on/off where you want it, with a lighter take-up.

[barkingspider]

Thank you all! I think I'm a little clearer on the concept, and appreciate you all for sharing your wisdom.

[Chrome]

I thought I remembered reading at some point someone (Tuna maybe?) mentioning the ideal length pin for an RT on/off in a classic valve, and I thought it was shorter than .750, I'm guessing to both reduce short stroking and shoot down when rapid firing on a classic with this setup. Anyone remember what that magic length is?

[Spider-TW]

I thought I remembered reading at some point someone (Tuna maybe?) mentioning the ideal length pin for an RT on/off in a classic valve, and I thought it was shorter than .750, I'm guessing to both reduce short stroking and shoot down when rapid firing on a classic with this setup. Anyone remember what that magic length is?

.750 allows for manufacturing tolerances and some overlap in the function of the on/off against the release of the sear. "Finger tight" on the field strip screw easily varies that height 0.010 from person to person. If you are consistent in your assembly, you can shorten up any one setup right up to the edge of operation. That puts extra wear on the tip of the sear and the edge of the bolt. If you consider those parts consumable, the wear is not so bad. However, you will have a hard time ever wearing out a sear and bolt on a classic that are maintained with a good spring and a .750 pin.

[BassdudeBTB]

Does anyone know the ideal length for a Classic RT valve to increase the Sweet Spot? I have a .750 pin in there now and there is almost no sweet spot at all even with 1050psi input pressure. Trigger seems to be the correct distance from the rod when aired up, but no luck with the RT sweet spot. (LVL 7 bolt, stock trigger/frame)

[Tunaman]

Does anyone know the ideal length for a Classic RT valve to increase the Sweet Spot? I have a .750 pin in there now and there is almost no sweet spot at all even with 1050psi input pressure. Trigger seems to be the correct distance from the rod when aired up, but no luck with the RT sweet spot. (LVL 7 bolt, stock trigger/frame)Go down to .740 but not too much more or you risk wearing out your bolt and sear. The shorter the pin from stock, the more you risk.

[JKR]

Just curious because I have been tempted to replace my stock L7 on/off pins with RT pins to "improve" trigger pull on my Classic valves - will replacing the pins with same length RT on/off pins cause any difference in bolt/sear wear?

What is the standard factory length on the Classic on/off pins?

[Tunaman]

Standard size is .750. You can't just change the pins. You must change the whole on/off.

[Cyco-Dude]

Does anyone know the ideal length for a Classic RT valve to increase the Sweet Spot? I have a .750 pin in there now and there is almost no sweet spot at all even with 1050psi input pressure. Trigger seems to be the correct distance from the rod when aired up, but no luck with the RT sweet spot. (LVL 7 bolt, stock trigger/frame)
what frame are you using? if it's a benchmark frame, it'll be much harder to sweet-spot. also, reactivity depends on the friction in your on/off o-rings, in addition to input pressure and pin length. the looser the fit, the easier it is to get it to bounce. up to a point of course, beyond which it will leak.

on a tangent, have you tried just walking the trigger instead of getting it to bounce? i have an rt classic with a benchmark frame that doesn't bounce at all at 975 psi, but i can walk it like an electro lol.


Just curious because I have been tempted to replace my stock L7 on/off pins with RT pins to "improve" trigger pull on my Classic valves - will replacing the pins with same length RT on/off pins cause any difference in bolt/sear wear?

What is the standard factory length on the Classic on/off pins?
you can use an rt on/off in a classic valve; as posted in this thread it will give you a lighter trigger pull.

[BassdudeBTB]

Thanks Tunaman. I thought to myself how can I achieve this effect without grinding the pin down... (Since I don't have another at the moment)

So I experimented a bit and made 0.004" & 0.009" shims with a leather hole puncher from thin plastic laminator sheets and put them in my on/off and BAM! Off it went. It was hard not to shoot full auto.
From 0" to 0.015" is the full range I found for the trigger to work. (full auto to not shooting at all.)
With just the 0.004" plastic shim it has a large sweetspot and can easily rattle off bursts of 2 to sometimes even 8 rounds! I have to practice with it a bit. But I played a few games with it last Sunday without any shims and left my on/off a quarter turn loose and it shot well. It seems shimming the on/off is the way to go for now since it is easily reversible.
I must note that over-shimming won't allow the valve to slide back onto the body.

Cyco-Dude - I have a stock frame & trigger. I'm not sure how to change the friction of my on/off o-rings predictably besides maybe different lubricants... I keep my mag well lubed :p

[Cyco-Dude]

I have a stock frame & trigger. I'm not sure how to change the friction of my on/off o-rings predictably besides maybe different lubricants... I keep my mag well lubed :p
well, it's usually a bit stiff with new o-rings, and just gets better over time as they wear in. some o-rings are tighter than others though, and you can test the fit by simply pressing the o-ring onto the fat end of the on/off pin.

[BassdudeBTB]

well, it's usually a bit stiff with new o-rings, and just gets better over time as they wear in. some o-rings are tighter than others though, and you can test the fit by simply pressing the o-ring onto the fat end of the on/off pin.

Yeah you are right, o-rings come out of manufacturing with slight variations in dimensions. I did put new o-rings in recently so that may be an issue as well. Thanks for the input, I will try a few of the spares I have to see how it fits.

[BassdudeBTB]

So I played a few games with it and the orings seem to have broken in nicely. I can sweet spot it if need be and shoot single shots without losing control and bursting off shots. I will need a lvl 10 bolt if I really want to do bursts. I am hesitant though since everyone says they are finnekey at best in Florida... Is this true?
I don't see any definitive descriptions of why and under what conditions, I am just told due to temp changes and humidity here not to bother with it... Is there a way to properly set it up and not worry about it for a while?

[Spider-TW]

So I played a few games with it and the orings seem to have broken in nicely. I can sweet spot it if need be and shoot single shots without losing control and bursting off shots. I will need a lvl 10 bolt if I really want to do bursts. I am hesitant though since everyone says they are finnekey at best in Florida... Is this true?
I don't see any definitive descriptions of why and under what conditions, I am just told due to temp changes and humidity here not to bother with it... Is there a way to properly set it up and not worry about it for a while?

Weather change in Florida??? I've never had any problem with humidity (we got some). I also have not had any identifiable trouble between 110F to 40F. One weekend I shot 2 1/2 cases at Blanding MOUT on two level 10 automags. I only switched for entertainment value between an X-valve and a pneumag. If they are already on the loose side of the seal, getting cold can push them over the edge, but I've never had to go back when the weather warmed back up.

I think going_home runs level 10s mostly. (in Florida, or used to be there :P)

[BassdudeBTB]

Weather change in Florida??? I've never had any problem with humidity (we got some). I also have not had any identifiable trouble between 110F to 40F. One weekend I shot 2 1/2 cases at Blanding MOUT on two level 10 automags. I only switched for entertainment value between an X-valve and a pneumag. If they are already on the loose side of the seal, getting cold can push them over the edge, but I've never had to go back when the weather warmed back up.

I think going_home runs level 10s mostly. (in Florida, or used to be there :P)

That sounds pretty good! Was it difficult to get it right? Was there a break-in period 'till it settled in? I found this to be the case with my on/off...

[Spider-TW]

That sounds pretty good! Was it difficult to get it right? Was there a break-in period 'till it settled in? I found this to be the case with my on/off...

Many people break them in by shooting something like 1000 times, after which you would expect to go to the next size "smaller" carrier. Some people play with them new until they leak and just go prepared. If I want to take a new L10 o-ring on an out of state game, I have polished the mold lines off the inside with a rod and rubbing compound. They are not bad if you take the time to read and understand the instructions and how the bolt works.

If I was limited to a single automag, it would have a level 10 bolt. I still keep a level 7 in a pump, a pistol, and a "classic classic", but anything of medium paint volume and up gets a level 10.

[BassdudeBTB]

Many people break them in by shooting something like 1000 times, after which you would expect to go to the next size "smaller" carrier. Some people play with them new until they leak and just go prepared. If I want to take a new L10 o-ring on an out of state game, I have polished the mold lines off the inside with a rod and rubbing compound. They are not bad if you take the time to read and understand the instructions and how the bolt works.

If I was limited to a single automag, it would have a level 10 bolt. I still keep a level 7 in a pump, a pistol, and a "classic classic", but anything of medium paint volume and up gets a level 10.

Ok thank you! I think I'm going to invest in one.
I plan on doing my homework before any mods or tinkering, especially with AGD products since they are so well thought out.
Could you explain the way you basically sand the mold lines off with rubbing compound? Do you mean like TurtleWax for auto paint? (Not the wax)
What rod would I use? Not a wooden dowel rod right? I have some mini precision files but I feel like they would damage the o-rings...

[Cyco-Dude]

So I played a few games with it and the orings seem to have broken in nicely. I can sweet spot it if need be and shoot single shots without losing control and bursting off shots. I will need a lvl 10 bolt if I really want to do bursts. I am hesitant though since everyone says they are finnekey at best in Florida... Is this true?
I don't see any definitive descriptions of why and under what conditions, I am just told due to temp changes and humidity here not to bother with it... Is there a way to properly set it up and not worry about it for a while?
sounds like a load of nonsense to me. they are fine. no need to prepare your o-rings; just use it. if it leaks, it takes all of two minutes to swap carriers.

the setup issues of the level 10 bolt are way overblown...it's simple to install, and simple to tune. it's a five-minute job, seriously.

[BassdudeBTB]

sounds like a load of nonsense to me. they are fine. no need to prepare your o-rings; just use it. if it leaks, it takes all of two minutes to swap carriers.

the setup issues of the level 10 bolt are way overblown...it's simple to install, and simple to tune. it's a five-minute job, seriously.

This makes me feel a bit better also... I read the instructions & saw the animation of the mechanism and read a bunch of the issues people had and it seemed straight forward to me...
I wasn't sure if they were just not mechanically inclined and making mistakes during setup (some def. were), or if there was a serious problem with the system, which seemed inconsistent with AGD products I have seen so far...
This being my first Mag I didn't know what to believe... There is a lengthy thread on LvL 10 issues so it made me a bit weary to go for it after reading some of the posts.
I thank you guys for your advice on this matter.
I will order one today most likely and post how it goes.
I won't cry about simple crap that is clearly explained in the manual & in videos on youtube either lol.
I'm only going to ask if I get seriously stuck to the point of not using it.
Thanks again everyone for your advice! :D

[Spider-TW]

There is a lengthy thread on LvL 10 issues so it made me a bit weary to go for it after reading some of the posts.

If you read through that, it is really all the same stuff except muddied by un-associated problems. We tease athomas that his post signature should be his L10 tuning instructions, which are pretty basic and in line with the factory instructions. After about the third time he goes over them, the OP will usually pick it up. :)

Not that you need to polish the o-rings, but yes fine turtle wax rubbing compound on a smooth rod that is snug fit in the o-ring will take the inside mold line off, which is what breaking it in does. I have a stainless rod that came out of an HP printer. Some of them are not bad to start with. If you can see the line without magnification, it will need breaking in one way or the other.

[BassdudeBTB]

If you read through that, it is really all the same stuff except muddied by un-associated problems. We tease athomas that his post signature should be his L10 tuning instructions, which are pretty basic and in line with the factory instructions. After about the third time he goes over them, the OP will usually pick it up. :)

Not that you need to polish the o-rings, but yes fine turtle wax rubbing compound on a smooth rod that is snug fit in the o-ring will take the inside mold line off, which is what breaking it in does. I have a stainless rod that came out of an HP printer. Some of them are not bad to start with. If you can see the line without magnification, it will need breaking in one way or the other.

Well, I ordered it and an RT Parts kit just to have extra o-rings and what not...
Looking forward to getting it installed & all tuned up!
Burst fire mode is in sight! My Q-Loader should feed it nicely for about 4 seconds lol!

[BassdudeBTB]

I installed my level 10 bolt and got it working but I need to chrono it to properly tune it. I noticed however, that my sweet spot on my trigger is gone. I turned up the velocity as needed to make it fire and left my shins in the on/off (0.012" total) but no more sweetspotting... I'm hoping the chrono reveals that my velocity is still too low and more pressure will fix it... I did however use my 2 non flatline tanks running about 850 & 950 psi output. My flatline tank is empty at the moment but I run it at 1050 psi output.
I am not certain that velocity adjustment will have any effect on the trigger bounce, I think it's just purely input pressure... With my LVL 7 I can get trigger bounce with these tanks and the 0.012" of shims, so I'm not sure where to go from here exactly.

[Cyco-Dude]

I installed my level 10 bolt and got it working but I need to chrono it to properly tune it. I noticed however, that my sweet spot on my trigger is gone. I turned up the velocity as needed to make it fire and left my shins in the on/off (0.012" total) but no more sweetspotting... I'm hoping the chrono reveals that my velocity is still too low and more pressure will fix it... I did however use my 2 non flatline tanks running about 850 & 950 psi output. My flatline tank is empty at the moment but I run it at 1050 psi output.
I am not certain that velocity adjustment will have any effect on the trigger bounce, I think it's just purely input pressure... With my LVL 7 I can get trigger bounce with these tanks and the 0.012" of shims, so I'm not sure where to go from here exactly.
this is normal; level 7 bolts are more reactive for some reason.

[BassdudeBTB]

But I've seen many mags online ripping off shots with the LVL 10 bolt... How do I achieve that? More pressure?

[Cyco-Dude]

But I've seen many mags online ripping off shots with the LVL 10 bolt... How do I achieve that? More pressure?

more input pressure (from the tank regulator, not by increasing velocity), broken-in o-rings, shorter on/off pin (up to a point). this should be doable with 900 psi, a .750" pin and broken-in carrier and on/off o-rings. this also depends on the frame used (intelliframe is easier to sweet-spot the gun with than a single or benchmark frame, for example). also, practice helps a bit.

[BassdudeBTB]

more input pressure (from the tank regulator, not by increasing velocity), broken-in o-rings, shorter on/off pin (up to a point). this should be doable with 900 psi, a .750" pin and broken-in carrier and on/off o-rings. this also depends on the frame used (intelliframe is easier to sweet-spot the gun with than a single or benchmark frame, for example). also, practice helps a bit.

Thanks that sounds pretty good. I'm sure once I fill up my flatline 45 tank it will make it easier. I could definitely use the practice also since this is my 1st mag. It was pretty easy with my previous LVL 7 setup. Do you know why the intelliframe makes it easier to sweetspot? Is it simply the double trigger?

[Cyco-Dude]

Thanks that sounds pretty good. I'm sure once I fill up my flatline 45 tank it will make it easier. I could definitely use the practice also since this is my 1st mag. It was pretty easy with my previous LVL 7 setup. Do you know why the intelliframe makes it easier to sweetspot? Is it simply the double trigger?
yes. and where the sear rod contact the back of the trigger on the intelliframe (lower, rod has more leverage to kick trigger forward) vs a benchmark frame (higher, rod has less leverage to kick trigger forward). it's also why intelliframes have shorter, but stiffer trigger pulls and benchmark frames have longer, but softer, trigger pulls.

[athomas]

The retro valve works on pressure differential between input(tank) and chamber. A level 10 chamber has more residual pressure left after a shot, so the pressure differential is less and therefore results in less force pushing on the on-off pin to reset the trigger. You can still achieve good results though, with the right setup.

A full tank will make all the difference. It will allow maximum air flow through the tank regulator and therefore through the mag valve. Air flow is just as important as pressure when it comes to having a reactive valve.

[BassdudeBTB]

Thanks athomas that explains it a bit more.

So I got my LVL 10 setup and it seems to be working fine. I can only get it to chrono properly with the yellow stock spring. Red spring won't cycle under 300+ fps. I got my flatline tank filled and tried different input pressures to get it to sweetspot but its not possible... I cranked the pressure so high that I blew a macroline and my LP gauge. I was way over 1500psi and still no rapid fire! This leads me to believe that my reg piston in my flatline may be bad or out of spec. It should've vented out the front from overpressurizing right?
I tried with and without the shims in the on/off and no luck.
I tried to follow Zak Vetter's guide to rapid fire mags and I set my sear rod to 1mm from the trigger with no effect. (I used a feeler gauge to precisely set it and I marked the starting position so I can set it back.) Im stumped...
If I shorten my on/off pin, which side do I have to grind? I would think its the thin side but I don't know for sure... I believe it lowers the top part so it seals with less of the length of the fatter top part in the top o-ring.

Also should I enlarge the holes in the flatline for more airflow?
Would this destroy it?
I know AGD products are well engineered and I don't think others have had to do this but it's just a thought...

[Nobody]

Is this a classic valve? A RT'ing classic is more of a happy accident than in a RT mag or a mag that uses a ReTro/Emag/Xvalve.

[BassdudeBTB]

Is this a classic valve? A RT'ing classic is more of a happy accident than in a RT mag or a mag that uses a ReTro/Emag/Xvalve.

It's a Classic RT valve, on a Classic Automag RT.
I put a LVL10 in it.
I also made some shims that fit inside the stock on/off to mimic the effect of a shortened pin. (2 shims = 0.012") Easily removable. This worked great with the LVL 7 @ 1050 psi, but I would chop paint if I shot a long string.
Everything else in the valve is stock.
The gun has Doc's AC threaded adapter for barrels and a Q-loader. Everything else is stock.
I use a Flatline 4500 adjustable Reg to feed it air.

[Cyco-Dude]

It's a Classic RT valve, on a Classic Automag RT.
I put a LVL10 in it.
I also made some shims that fit inside the stock on/off to mimic the effect of a shortened pin. (2 shims = 0.012") Easily removable. This worked great with the LVL 7 @ 1050 psi, but I would chop paint if I shot a long string.
Everything else in the valve is stock.
The gun has Doc's AC threaded adapter for barrels and a Q-loader. Everything else is stock.
I use a Flatline 4500 adjustable Reg to feed it air.
what frame do you have on the rt? what o-rings are you using in the on/off? have you tried just walking the trigger instead of trying to bounce it?

[BassdudeBTB]

what frame do you have on the rt? what o-rings are you using in the on/off? have you tried just walking the trigger instead of trying to bounce it?

I have the stock carbon fiber frame. I believe they are the correct orings in the on/off but I have a fresh new rt rebuild kit I could drop in new orings. That's a good idea. I have a single trigger so I can't walk it but I can pull it kinda quick I guess. Since the LVL 10 the trigger feels kinda spongy with a longer pull... Maybe it's the orings?

[athomas]

I got my flatline tank filled and tried different input pressures to get it to sweetspot but its not possible... I cranked the pressure so high that I blew a macroline and my LP gauge. I was way over 1500psi and still no rapid fire! This leads me to believe that my reg piston in my flatline may be bad or out of spec. It should've vented out the front from overpressurizing right?

Also should I enlarge the holes in the flatline for more airflow?
Would this destroy it? The reg piston in the flatline should be fine. The piston has some variance and the gauge you are reading has some error. Don't alter the air ports. They flow quite well as is if everything is working as it should.

Install the valve without the bolt. Air it up with the trigger held in. Then gently let the trigger out until air starts to vent out the front. That will give you an idea where trigger is when the on-off closes. Then install the bolt and air it up and gently pull the trigger. Take note of when the valve fires. If the distance between where the on-off closes and the valve fires is close, it will be easy to RT. If the distance is large, it won't RT. If you have a large distance, you will have to get a shorter pin.

[BassdudeBTB]

I got it working!! It was the on/off o-ring at the top. It was too tight and making the pin stick. I replaced it and trimmed the pin to .743" and it rips now! The LVL 10 works well with the yellow spring for now. I'll do more tweaking after I play a few games with it tomorrow. Thanks a lot guys for all the advice and tips! This community rocks!

[Andrew lee]

So what happen did you get it reactive?