Come! Show Me Why I Am Wrong

[Z-man]

As some of you guessed, one of my pet peeves has been the seemingly groundless reasons that rapid-fire is not something you should do on your Automag.

I have heard it all; from the claim that it's a "malfunction of the valve" to claiming it's the short road to snapping the power tube. 3 years, 3 markers and now my own website later (BWAHAHA!) I am still not seeing it.

I would expect to run into the best minds of AO here to either explain why I am incorrect (or correct) in my logic. Have at it! My masterpiece! The pages that will bring closure to years of ambiguity!

http://www.zakvetter.com/Pages/Paint...rapidfire.html

[Steelrat]

Rapidfire is the work of the devil! Repent!

[Z-man]

NO ONE EXPECTS THE SPANISH INQUISITION!!!!!

[ZAust]

meh, all the cool kids dont need rapidfire to have a good time.

[AGD]

There is a good reason. When you bounce the sear on the RT valve the bolt rides the sear back to the home position. When the bolt comes all the way back, it bounces off the bumper and comes forward. If it was riding the sear, the sear has now moved up and catches the bolt on the rebound which acts just like a small hammer.

This pounding will eat up your sear and your bolt. Under normal pulls the bounce happens before the sear comes back up. This is also the reason we use a softer bumper on the RT valve.

See, there are intelligent reasons for everything we tell you.

AGD

[Z-man]

Hooray! Thank you Tom. I am glad to FINALLY hear a logical reason for this! So it's more those 2 things:

-The sear sliding along the bolt all the way back (thus rubbing away a larger part of it)

-And the bolt getting banged by the rebound of the "bounce"

Just out of curiosity then, what is happening in my video when the rapid-fire is slower? Is my finger pressure softening the bounce?

Also, does the same kind of thing happen when you are firing an E-Mag series marker at high speeds? I guess what I am asking is, is it the speed that is damaging to the bold and sear or is it that when you hold the sear with your finger you force the sear to wear against the bolt and cause that little hammering?

Doesn't that also happen when you fire the marker normally? When I pull the trigger it cycles so fast that I cannot remove my finger from the trigger fast enough to take the pressure off the sear before the bolt returns. Doesn't that mean the sear is being pushed against the bolt just like in rapid-fire?

In addition doesn't the bolt always bounce off the bumper and smack the sear tip?

Thanks for the help.

[my2crazyeyes]

Please don't be to harsh on me, I'm not sure about this.

"Doesn't that mean the sear is being pushed against the bolt just like in rapid-fire? "

I think the difference is that when you are rapid firing the sear isn't fully catching the bolt, it is just catching it on the very point (at least some of the time) since the sear doesn't have enough time to return fully. The bolt does "hammer" the sear under normal firing, but there is more surface area to catch the bolt since the sear is fully in position before the bolt starts to come forward again.

at least that's what happened to my sear (I think) maybe my spring was bad though I dunno.

Just a thought,

-Chris

[athomas]

You can rapid fire a mag. The problem arizes when you get the mag to runaway due to bounce.

During normal firng of a mag, the bolt returns and is stantionary before the sear is released to hold the bolt and recharge the chamber. There is no wear and tear.

When the trigger is held so that it continually actuates the gun due to the bounce, the sear is held just under the bolt so that they rub while the bolt goes forward and back. The sear is then pushed up to just barely catch the bolt and allow the chamber to recharge. The pressure held by your finger prevents any further upward movement by the sear. The continuing pressure held on the trigger results in another trigger pull once the retro on/off pressure is reduced and the firing process is repeated. Its this process that causes wear on the mag bolt and sear.

[Z-man]

Originally posted by my2crazyeyes
Please don't be to harsh on me, I'm not sure about this.

I HATE YOU I HATE YOU DIEIDIEIEDED!!!

Originally posted by my2crazyeyes
The bolt does "hammer" the sear under normal firing, but there is more surface area to catch the bolt since the sear is fully in position before the bolt starts to come forward again.

That is a very interesting point. I do think that could be a contributing factor in the wear. I still am not sure though how what Tom said above and what you have said here is true if I can do this maneuver (it's a 12MB QuickTime video)

It seems to me that if the speed of the rapid-fire can be varied in speed to that degree, something else must be going on here.

Originally posted by athomas
You can rapid fire a mag. The problem arizes when you get the mag to runaway due to bounce....

Did you read my 4 pages on rapid-fire that I posted the link to in my first thread? I address just about everything you said there.

(Click the "how to rapid-fire" link on the page)

http://www.zakvetter.com/Pages/Paint...ags_main.htmll

[my2crazyeyes]

I think the difference is when agd is firing at high rates they are making full trigger pulls. When you are holding the trigger in a spot and letting the sear rod (or what ever it is called) bounce off the trigger you aren't allowing the sear to compleate its full movement. It propably doesn't hurt to do it every now and again, but long strings of it probably isn't very good. Another thing you might want to think about is the heat generated from the bolt traveling on the powertube. The heat would wear away the oil on the tube, and cause wear on both the bolt and the tube. This probably doesn't do too much damage, but I suppose it could wear away enough to comprimise the strength of the tube.

-Chris

[Z-man]

Originally posted by my2crazyeyes
I think the difference is when agd is firing at high rates they are making full trigger pulls.

What do you mean AGD?

Originally posted by my2crazyeyes
Another thing you might want to think about is the heat generated from the bolt traveling on the powertube. The heat would wear away the oil on the tube, and cause wear on both the bolt and the tube.

Each time you fire the marker you expell a respectable volume of cool air. Whatever heat is generated by friction from the moving parts is negated and overwhelmed by the cool air the blows through the valve.

When the valve is fired quickly, it cools down from the cool expanded air. The faster you fire, the quicker the valve cools (untill its the same temp as the air passing through it)

[Korrosion]

Does this mean that bad things happen when you use hybrid mode and use the sweet spot where the electronics pick up the trigger pull but the mechanics kick the trigger back?

Originally posted by AGD
There is a good reason. When you bounce the sear on the RT valve the bolt rides the sear back to the home position. When the bolt comes all the way back, it bounces off the bumper and comes forward. If it was riding the sear, the sear has now moved up and catches the bolt on the rebound which acts just like a small hammer.

This pounding will eat up your sear and your bolt. Under normal pulls the bounce happens before the sear comes back up. This is also the reason we use a softer bumper on the RT valve.

See, there are intelligent reasons for everything we tell you.

AGD

[athomas]

When you use hybrid mode, the solenoid provides a complete trigger pull for you. The solenoid then holds the sear out of the way until the bolt is completely returned. You can't ride the sear using hybrid mode.

[phyregod]

Remove your trigger frame, get shorter screws and put your mag back together, sear and all, save for the trigger frame. Use the bottom of the sear as a trigger and see what happens when you fully pull the sear out of the way of the bolt. I had a classic mag that would shoot faster than anything I've ever seen or heared when you did that. Never put did balls in it though... Afraid that thirty chopped balls would be bad for the bolt and breech. It'll make you cackle with insane glee.

P.S. I would like everyone to know that the above rantings are very dangerous. That info is for informational purposes only, so if you blow your friggin hand off or pinch your nipple with some exposed part, it isn't my friggin fault.

[P8ntBallBoom]

My on/off pin has worn down now, too, and so I'm getting rapid fire. I did notice that when the trigger is held down with more pressure, my bolt sticks and I need to degas and everything.
Another thing I noticed......I chopped a ball!! OMG, I nearly fainted when I saw a chopped ball in my mag.....then I realized it was probably the year old paint I was using.

Anyways, it's a new on/off pin for me come Monday when I order it.

[AGD]

There is a HUGE amount of heat generated by the speed at which the valve recharges. The internal air of the chamber gets up to 180 degrees, friction on the parts is nothing. You guys can't just guess about whats happening in a marker.

AGD

[bleachit]

There is a HUGE amount of heat generated by the speed at which the valve recharges. The internal air of the chamber gets up to 180 degrees, friction on the parts is nothing. You guys can't just guess about whats happening in a marker.

AGD

is this the reason why a RT/X valve cannot be run on CO2?

[Z-man]

There is a HUGE amount of heat generated by the speed at which the valve recharges. The internal air of the chamber gets up to 180 degrees, friction on the parts is nothing. You guys can't just guess about whats happening in a marker.

AGD

I am not sure, but according to my calculations that was the slap being laid down.

[Plazmic]

See, now that's the kind of information I'm reading this for. And yes, I believe that was the slap being laid down.

[aut911]

No, basically the reason for why you cant run the RT/X valve on CO2 is due to the fact that the valve recharges SO fast, not to mention the fact that a long string would freeze a classic mag on a 70 degree day with an expansion chamber. Im guessing that the RT would be more susseptible to freezing than a classic because of the faster recharge rate. Its funny how one proppellent gas will freeze a valve with condensation, and another gas(HPA) will heat the valve to uncomfertable levels.

aut

[athomas]

The heat is generated by the compression of gas in the front chamber as the valve "recharges". In AIR valves it was not noticable due to the lower recharge rates. The retro valves generate heat because the gas is recompressed so quickly.

The freezing occurs at the back part of the valve where the gas decompresses from its input pressure. This decompression cause a drop in temp. The drop in temp causes the dew point of the CO2 to become lower. Therefore, some of the CO2 becomes condensation in the passages. The condensation can cause the o-rings to freeze and stop sealing. The gas absorbs heat energy from the valve and o-rings to become a gas again. This lowers the temperature of the valve passages. The more heat that is drawn from the valve, the cooler it gets. So, the faster you fire, the more heat is drawn from the valve. The heat from the recharge(even in a retro valve) is not a factor because it is discharged behind the ball. In a one shot scenario, the heat will help thaw the freeze and effectively cancel it out if the o-rings don't freeze first causing uncontrollable venting, which would result in a "runaway freeze" condition. This would only happen in the retro valve. The AIR valve handles the lower rates of fire and lower recharge rate quite effectively. Air has a different point at which it turns to liquid. Therefore, under normal and extreme operating conditions, the compressed air will never condensate. The low rate of heating and cooling are effectively cancelled out due to the lower recharge rate of an AIR valve. In a retro valve the front chamber heats while the drop in temp is dispersed over the volume of the tank. The valve heats because it sees more heat than cooling.

There is so much more that could be said here but hopefully this gets a basic explaination across.

[Z-man]

Well you did leave out why the CO2 freezes the o-rings even though both CO2 and the HPA discharge at the same rate. The whole phase change aspect of the CO2 is the largest cause of the freezing o-rings. Whenever you have a substance change phases (solid -->liquid, liquid-->gas, solid-->gas) it requires MUCH more energy per molecule than to raise the temperature of those molecules in the same phase.

Water is a good example. From 0C - 100C at 1 atm, 1 gram of water takes 1 calorie of energy to raise it's temperature 1C. It does not matter if its from 5C to 6C or 88C to 89C, under those conditions, that is the energy required. Now, at 1 atm water undergoes its phase change to steam. While it takes a mere 1 calorie to get liquid water from 99C to 100C, it takes 100 calories to change that same 1 gram of 100C liquid to 100C gas. Now CO2 does not have the same energy requirements (they are a bit less) but the same idea applies

That is the underlying reason for CO2 freezing down the Automag AIR valve and the reason for ANY marker that uses CO2. Unlike compressed air tanks that store N2 is the same phase, CO2 tanks (like a 20 oz for example) have 20 oz of liquid CO2 that has to have a crap load of energy put into it to change it into a gas state. Where does that energy come from? Largely that surrounding air and the person's hands. This is one reason why a coiled remote is helpful when using CO2. It adds a large surface area that can absorb the surrounding air much better and sunlight (as they are black).

The other thing you might need to consider is the "faster vs. slower" recharge rates. Mechanically, the valve design does not "speed up or slow down the incoming air (please explain to me if I am off on this). The reason for the slower recharge is because of the 2 very different gas systems.

At best when CO2 is room temperature (~21C) the vapor pressure of the CO2 is about 830psi. There is no regulator on a CO2 tank, whatever pressure is in there, that is what you got. That is BEFORE you start shooting the marker and dropping the pressure of the tank and thus causing some of the liquid to undergo it's phase change. Since it's near impossible at the CO2 systems are setup currently to keep the temperature constant in the air system so what happens is the the temperature (and therefore the pressure) of the CO2 tank drops as you fire the marker This problem is exacerbated when you shoot very fast, over long periods of time. This is the explanation of shoot down on CO2 tanks.

To add to the problem, unless you let give the CO2 sufficient time to warm up (somewhere between the tank and the valve) you don't get very consistent input pressures and thus shots on the marker. Also if you don't restrict the liquid from entering the marker, the phase change will occur in the AIR valve and THERE is where the problems arise.

First the evaporating CO2 freezes down the valve (no big deal for the steel but NG for the urethane o-rings.)

And second, the now evaporated CO2 hs a MUCH larger pressure than what originally came in the valve. This will give you a nice zinger if you gave it time to warm up. Say you are shooting nice and fast with your AIR Mag on CO2 and things start to freeze down and you see lots of that white stuff coming out . Then you decide to crawl around for a few minutes nd get into position. All that time the Co2 has been warming up and expanding. When you take that next shot you could pull over 350 just from letting it warm up. This is why HPA is superior; NO phase change, NO huge energy requirements and relatively consistent performance.