Closed v. Open (Bolt)

[SlartyBartFast]

Originally posted by Paladin

On the roundness of paint in barrels:

Not entirely true as it does not take into account the distortion of the ball as it is compressed from front to rear by the g-forces of acceleration. This causes it to tighten against the side wall of the launch tube and create friction at the sides which adds to the distortion into a cylindrical shape for at least part of its travel down the tube.

Sounds all scientific and even believable. But the contents of a paintball are largely uncompressable. The gas pressure at the back of the ball is equally distributed and imparted on the uncompressible liquid fill which in turn pushes on the front of the shell. This all dictates that the paintball remains round. Tom Kaye has claimed high speed photography not showing deformation. I tend to beleive him, and his results coupled with the nature of the forces seem to point to a round paintball.

But that's all beside the point. What's the magical difference between open and closed bolt? In the barrel the forces are identical.

On the WARPIG experiment:

No, that is not what it proved at all. That test only proved to me that the gun was not tuned properly to maximize the potential of true closed bolt operation. If the gun was not optimized for best results in one mode, it isn't hard to see why it would show similar results in another mode.

What's the magical optimisation that will help closed bolt operation? While I respect what PPS does with markers, valves, and regulators, no hint is given here as to what magic the elves are supposed to be accomplishing. What optimisation should have been done? Why shouldn't the same optimisations be done to the open bolt?

The only "FACT" shown is that THAT gun on that day did not show a benifit to closed bolt operation. On the other hand, if the same bolt/hammer arrangement was used for both tests (closed and open bolt firing) the results would have to be the same. True closed bolt operation requires that the chambering cycle be completely seperate from the firing cycle. Bolt and hammer operating independantly. Open-bolt firing puts chambering of the round and firing it in the same move.

If you read the test descrition it seems to me the firing was separate from the chambering. In fact it would seem the gun was operated as a 'bolt action'. Meaning that any claims this wasn't 'TRUE CLOSED-BOLT' are somewhat far-fetched.

What's the magical rest time that a ball needs to recover from the 'abuse' from the bolt? Leading to the question of at what point does closed bolt, if you beleive it has an advantage, become the same as open-bolt?

Where's the proof that the bolt deforms the ball so as to affect consistency?

A barrel can only be "better" if it is different than the one it is being compared to and the best barrel for a "closed-bolt" firing gun may not be the best barrel for the same gun operating in "open-bolt" mode.

What's the magical force that makes the barrel requirements different? What are the differences that do make a barrel better?

[Nomad]

Then perhaps the next Open bolt vs Closed bolt test done:

1) With an Autococker with the Firestorm Kit equipped on it.

2) Using an aftermarket barrel, perhaps an Aradus as it can be adjusted for multiple bores, thus having a better chance for paint to barrel match.

3) Using a HPA tank and another regulator (perhaps a Palmers Stabilizer and one of those AGD Flatlines. We're taking one shot at a time, shoot-down probably not a problem).

4) Making the test in indoor conditions, to reduce the chance of wind being a factor (don't think wind can be completely eliminated in any condition).

5) Have the target at about 30 to 40 feet, to simulate normal shooting distance in a game.

6) Use a good quality paint. (No duh....)


That's my suggestion.

[SlartyBartFast]

Originally posted by Treghc
does no one pay attention to what I say?

Standard reaction to reasoned logic attacking a religiously held belief.

[SlartyBartFast]

Originally posted by Nomad
Then perhaps the next Open bolt vs Closed bolt test done:

Sounds like a fine setup.:)

The only thing is that besides gut feeling and prejudices, no one has yet come up with any real reason to discredit the original test.

If there were any real reasons I'd like to hear them and be shown some proof that the reasons are valid.

Beyond Magic and Elves, the following equation will be true: Same paint to barrel match, in a decent barrel, same exit velocity, same result.

The only thing that will affect the 'accuracy' is the hand pulling the trigger and pointing the marker.

Originally posted by ezrunner
The debate is BS open/closed/electro
The game is not in the gun, it is in the player.

What he said!

But it takes REAL balls to go up against Electros with a Splatmaster.

[Paladin]

Originally posted by Nomad
Then perhaps the next Open bolt vs Closed bolt test done:

1) With an Autococker with the Firestorm Kit equipped on it.

Getting an accurate evaluation of the difference between closed and open bolt firing will depend on whether or not the hammer and bolt function independantly or connected together and functioning in unison. If the bolt and hammer are not connected and moving independantly, true open bolt firing is not being accomplished. Electronic timing of the bolt movement and hammer release can present a miss-conception of open bolt operation.

[i]
2) Using an aftermarket barrel, perhaps an Aradus as it can be adjusted for multiple bores, thus having a better chance for paint to barrel match.
[/B]

One of the biggest considerations for the consistency and accuracy of a barrel on a closed bolt firing gun is a provision for making sure that the ball stays in contact with the face of the bolt when the ball is chambered so each ball is fired from the exact same location in the barrel. A ball fired from even a little bit forward of the bolt will generally be a bit lower in velocity than one fired from a position that is tight to the face of the bolt. That is the reason that the barrels on all PPS markers (all closed bolt firing guns) are honed to an eliptical shape in the bore and have a containment system at the rear of the barrel (called the "wedgit" system) to insure consistent positioning of the ball when it is fired.

[i]
3) Using a HPA tank and another regulator (perhaps a Palmers Stabilizer and one of those AGD Flatlines. We're taking one shot at a time, shoot-down probably not a problem).
[/B]

4) Making the test in indoor conditions, to reduce the chance of wind being a factor (don't think wind can be completely eliminated in any condition).

[i]
5) Have the target at about 30 to 40 feet, to simulate normal shooting distance in a game.
[/B]

Stretch that distance out to 60 to 100 feet and you will more easily be able to measure the difference in shot pattern. Especially if the gun(s) are fired from a vise and take the shooter out of the equation.


6) Use a good quality paint. (No duh....)


That's my suggestion. [/B][/QUOTE]

[Paladin]

Sorry, but I don't deal in Magic or elves.

If you accurately define the difference in operation between firing from the open bolt position and firing from the closed bolt position, you will minimize your confusion.

Originally posted by SlartyBartFast


Sounds all scientific and even believable. But the contents of a paintball are largely uncompressable. The gas pressure at the back of the ball is equally distributed and imparted on the uncompressible liquid fill which in turn pushes on the front of the shell. This all dictates that the paintball remains round. Tom Kaye has claimed high speed photography not showing deformation. I tend to beleive him, and his results coupled with the nature of the forces seem to point to a round paintball.

But that's all beside the point. What's the magical difference between open and closed bolt? In the barrel the forces are identical.



What's the magical optimisation that will help closed bolt operation? While I respect what PPS does with markers, valves, and regulators, no hint is given here as to what magic the elves are supposed to be accomplishing. What optimisation should have been done? Why shouldn't the same optimisations be done to the open bolt?



If you read the test descrition it seems to me the firing was separate from the chambering. In fact it would seem the gun was operated as a 'bolt action'. Meaning that any claims this wasn't 'TRUE CLOSED-BOLT' are somewhat far-fetched.

What's the magical rest time that a ball needs to recover from the 'abuse' from the bolt? Leading to the question of at what point does closed bolt, if you beleive it has an advantage, become the same as open-bolt?

Where's the proof that the bolt deforms the ball so as to affect consistency?



What's the magical force that makes the barrel requirements different? What are the differences that do make a barrel better?

[pbjosh]

My thoughts and opinions-

This is my simple, no science added, total WAG, and I know that those things are not appreciated in Deep Blue.

I personally thought, as long as the valve is consistant and areas such as barrel and paint are decent, that the only other factor that could affect accuracy in the feilds of Open vs Closed bolt is the movement of the ball as the air is applied to it.

In-accuracy is from a ball incurring to much spin. You want to have a small, slight spin on the ball, just to counter static boundry affect issues (sorry to add science to a WAG), but too much spin pulls it to the side it rotates against.

Now, if a gun incurrs pre-spin on the ball, so that the ball already has spin (such as forward or 'down' spin) as the air hits it then the related spin is increased (according to this WAG.) This would be influenced by guns that had loose breeches, and had a fast cycling bolt. If the ball was able to stop completely before the air hits it, I would think that the you would loose the incurred spin. Or if the gun has a tight breech, so that the ball spin is minimised. Also for guns that had breeches that were too tight, or a barrel transition point that could also add to the spin.

But most of this is a guess. I am most likely wrong, and even not close in any manner. DO NOT TAKE THIS AS TRUTH! And there would be quite a few other issues, such as valve type and such.

I do know of a guy who has a very clean closed bolt Angel. It can be ran either Open of Closed by turning the bolt, with no difference in performance besides that. When he gets finished with it, he can do some true Open vs Closed with a little more of a top of the line gun (sorry Bill!), one that also has had a history with its accuracy and range.

Please feel free to pick this apart, thats why I dropped it here.

Josh

[ezrunner]

mechanical repeatability

Paladin (all reverence due):
I am not arguing one is better than the other, I have this to pose.

If say a lapco autospirit barrel, and paint that mic's out to .688 were used.
That should ensure a tight fit in the breech for each shot.
We also assume the ball is pushed into the breech of the
barrel on this marker before air
is introduced.

What does the small amount of time that the bolt is at rest
before the valve is openned buy us?

I honestly think the debate will never end, and that marker a can be shot
as well as marker b with the
right setup. This is just
a clarification issue I think
could be interesting.

Thanks for any input.

-rob

[bjjb99]

Would a pump-action Phantom with an autotrigger be an appropriate open bolt equivalent? You can cock the marker, hold down the autotrigger, and move the pump forward to fire, thus firing from an open bolt position. If you controlled the pump arm with a pneumatic ram (for more consistant shot to shot pump motion), you could operate the Phantom in either open or closed bolt mode simply by choosing whether the trigger is continually squeezed (autotrigger "open bolt mode") or only squeezed after the bolt is in the forward position (normal "closed bolt mode").

Bench mount the Phantom, clamp the trigger down, and just cycle the pump. Measure each shot's velocity. Measure the shot grouping at a fixed distance. Remove the trigger clamp, install a solenoid to move the trigger (so no hands touch the bench mounted marker during firing), and repeat the velocity and grouping test. Repeat the test as many times as you like at different target distances.

Just a thought for a reasonable open/closed bolt testbed. Feel free to hurl rotten fruit my way if you see fit to do so.

BJJB

[SlartyBartFast]

Originally posted by bjjb99
Would a pump-action Phantom with an autotrigger be an appropriate open bolt equivalent?

Yet another good suggestion for a test. But I guess Palladin will have something to say about 'true-open-ness'.

[SlartyBartFast]

Re: mechanical repeatability

Originally posted by Paladin
Sorry, but I don't deal in Magic or elves.

If you accurately define the difference in operation between firing from the open bolt position and firing from the closed bolt position, you will minimize your confusion.

With all due respect you don't get away with blithe comments in Deep-Blue (or maybe you do as you refuse to give out any technical ideas). If I'm confused it's because you're offering no new information. How about some meatier explainations?

What can be more 'true-closed bolt' than bolt action? That was how the Stingray was fired in the test.

Sounds to me that you're just arguing tiny semantics (and millionths of a second) to try a maintain a point that puts your own products in a better light.

Which is really unfortunate as there is no doubt about it, your guns are good and amongst the best. But you're not providing much in the way of proof or substance here.

Originally posted by ezrunner
What does the small amount of time that the bolt is at rest before the valve is opened buy us?

And that's the million dollar question. At what rate of fire does open-bolt equal closed-bolt if you are to believe one has an advantage over the other? Under rapid fire, you're talking milliseconds between the mythical stop and stabilisation of the ball and the injection of gas.

Still waiting for some kind of proof that once jammed into a correctly sized barrel how any of the theorising of bolt/ball dynamics really has any effect.

A well tuned cocker (closed-bolt) and an XMag (open-bolt), both with the same barrel (as both are cocker threaded and use detents), shooting the same velocity, will both perform identically.

[AGD]

And the debate rages on..... I must say that this debate is much more enjoyable here in Deep Blue than other places where it ends up "just because!"

I would like to ask this learned group, if the debate is over which one is "better" what magnatude of "better" does it have to be to constitute proof?? If a closed bolt shoots one ball out of 1000 more accurately does that count? How about 1 in 100 or 1 in 20??

In astrophysics this is asked all the time "how do you know you really detected something?" In that field they do it statistically with either a 2 sigma or 3 sigma requirement for a clean believeable detection of difference.

Some of you must know about statistics here and understand what a 3 sigme detection means. I would sugest you argue the right protocall for a test in hopes that someone will actuall do it and put this to rest.

AGD

[nippinout]

Statistics, eh?

You question the importance of only having a few shots more accurate than open bolt.

But all of this is quite moot.

A sphere is a sphere is a sphere.

Many people have argued that the Warpig test used low-end equipment for it's open/closed bolt test. I whole heartedly agree.

But as in every test, your results must be repeatable and you must minimize your variables.

Why weren't nylon balls used? One might argue that results from using nylon would not matter because we do not use nylon balls on the field. But, when we can't have trials that aren't exactly the same, you throw the hypothesis out the window.

Now if we talk about 3 sigma, that's a whole other can of worms.

For those unfamiliar with statistics, sigma is a notation used so we can estimate the percantage of a population within a range of the median determined by sigma.

Tom, in your example of having 1 out of 100 shots more accurate than open bolt, if it is important enough. As a marketing standpoint, having even 1 out of 1000 will have a large amount of people shelling out for a new gun. As a functional standpoint, no. So where do we determine importance? If it is functional! :)

Three sigma is quite a large percantage of a population. Two sigma is also quite large.

Jebus, astrophysics has crazy amounts of assumptions and approximations. My physics TA was a grad student in astrophysics and told us how they make calculations where they round off a few hundred billion miles and still be okay.

Let's use our handy dandy Paintball Trajectory Calculator at http://home.attbi.com/~dyrgcmn/pball/trajectory.html

At 300 fps, we have the ball terminating at a range of 118.7 feet, .427 feet high, and 138.1fps.

At 310 fps, we have the ball terminating at a range of 121.4 feet, .450 feet high, and 140.1fps.


At 290 fps, we have the ball terminating at a range of 115.9 feet, .404 feet high, and 136.0fps.

I have no clue why the ball terminates with velocity and elevation, but let's take this data as is.

Let's say our target is some dude at 118.7 feet away from us. He's sticking out his bum out the side of his bunker. At 300fps, we got him. At 310fps, the ball travels less than 3 feet more and .23 feet higher in elevation. Basically, we got him at this range too. At 290 fps, we have a similar situation where the target is large enough to tag his bum.

I took some liberty in the assumption of the ranges of the 3 velocities hitting him, but the end elevation are within .046 feet in a range of 5.5 feet. That target area is a pretty tight one.

So with a velocity fluctuation of +/-10fps, we have a pretty accurate gun. And this is for a target over 100 feet away. Would you be happy with a gun that shoots +/-10fps? It's pretty damn accurate, but it isn't a selling statistic.

So how accurate is your gun? As accurate as your shot to shot accuracy. I guess I should be asking how consistent is your gun. Consistency is key. Paintballs aren't accurate shot to shot. Once again, a sphere is a sphere is a sphere.

When a noob asks you what is the most accurate gun, you don't tell them which gun, but rather just to get a gun that will make them happy and a freak kit (Or a bore that fits their fields paint best).

I say we make a new discussion about the Advantage shell. It has a roughed up texture as compared to the other glossy smooth shells. And the stuff just SMELLS like my grandma deep frying fish in a wok of dumpster juice.

So in conclusion, I believe that there is little benefit to accuracy from improving shot to shot accuracy. The only PRACTICAL benefit I see in improving consistency is in tourney ball. A consistent gun will allow you to run a velocity as close to 300fps possible without going over and getting penalized for hot shots.

Your gun isn't accurate. It's accurate enough. :)

[SlartyBartFast]

Originally posted by nippinout
Your gun isn't accurate. It's accurate enough. :)

Too True!

If we really want to look at accuracy statistically, I already proposed a method for testing barrel length differences in another thread.

http://www.automags.org/forums/showthread.php?s=&postid=513906#post513906

But to say neither open nor closed-bolt makes a difference we're still debating those that would have us beleive there is some magical/unexplainable force working on the ball after it leaves the barrel. But they contend that it can be optimised for.

[pbjosh]

Personally-

I think accuracy, or inaccuracy, itself needs to be looked at. What causes problems, what would make one shot, not gun, more accurate than another.

Alot of people have taken the easy way out and said "all the guns firing at the same velocity shoot the same distance" but don't think that is right. Look at the Flatline barrels. That alone breaks the statement all to bits.

Look at a baseball pitcher. He can throw a ball at the same speed, but with incurred spin on a ball he can control the distance and do, well, if I could make a gun that shot like a baseball pitcher..............

With every ball, the spin it has is the ENTIRE issue with accuracy. So, if a gun, barrel, ball, magic elves, can make the ball spin at the right rate, then you can have the range and accuracy inherent in the system.

I think that some gun systems add an amount of bad spin. As I stated above some of the reasons, what needs to be put down first, above ALL the velocity issues, is SPIN.

Spin is the issue at hand, not velocity, not Closed Bolt or Open. If you can have the right about of spin you have good range and accuracy. If you have bad spin, then you don't have either.

The arguement of velocity = range does not work when shooting a round projectile. Because spin is going to affect both portions of it.

Saying the range is totally a factor of velocity puts you in the "Earth is Flat" group.

Josh