Dual stage spring?

[Magluvr]

Ok, reading the different posts I found that to increase efficiency in the mag, one possible solution would be to get the bolt to come back sooner to help keep the residual pressure as high as possible in the dump chamber. So, (first let me say that I know nothing about the mechanics of springs) would it be possible to have a dual stage spring? So that at first the bolt would be able to move as easily as the original spring, maybe even softer, then as it the bolt stem starts releasing the air for the ball have it start building more strength. In essence the bolt would travel as normal but would be cushioned at the end to aid in less kick (since the bolt isn't as suddenly stopping and changing directions) and to help push the bolt back sooner to keep up the residual pressure in the dump chamber.

I hope that makes sense.

[dyst0pia]

I think I know what you are talking about. We used to use them in R/C trucks, since you could have a really responsive spring for a little bit, then have it get stiffer so that your whole shock wouldn't be used for little bumps. I believe they are called progressive springs? Progressive in the sense that the rate changes as you compress the spring.

I don't know too much about getting more efficiency from a mag, but if it would be possible to get a couple of these springs made, I would definitely help test them out.

[Magluvr]

That post was kinda hurried, so here are some more thoughts that just popped up.

Disadvantages:
Would the spring not be as durable and need to be replaced more often, even though its not often you have to replace the spring anyway?

Neutral:
This system would probably have to utilized in conjunction with lx. Without it the "strong part" might be able to seal up the bolt with the power tube, but the tube and dump chamber might have enough residual pressure that the "soft part" would be able to fully reset the bolt. That would be horrible, the gun would be hanging in limbo, unable to fire. The lx would be able to work though because as it is made so that air can flow by the bolt stem. (If you don't know what I refereing to, please refer to the illustrations on the site about the lx's low pressure stage.)

Advantages:
Because of the progressive spring, the gun may be able to use less pressure in the dump chamber.

#1 If left this way, the gun would be able to use the pressure at the "bottom" of the tank that the mag can't otherwise use (aka more shots).

#2 However, if you wish for even better efficiency, instead keep the pressure the same (~400psi) and utilize the "de-volumizer" mods, which I saw somewhere on the forum. This would result in even better efficiency but the gun still wouldn't be able to use the shots at the "bottom" of the tank.

The higher pressure setup (#2) would be able to recharge faster than the non-modded setup because there would be less volume to fill and there would be less of a pressure differential to make up for.

The lower pressure setup (#1) would probably recharge at the same rate as the non-modded setup because there is still as much volume to fill, but less of a pressure differential. However, it would even out because as the valve is configured the channel to and from the on/off assembly is unchangeable and not as much air per energy would be able to flow through.

This is all, of course, providing that the progressive spring idea works out.

[athomas]

Part of the problem with the level 10 having efficiency issues is the higher amount of residual pressure in the chamber after it is done shooting a ball. The higher force of the spring also acts like a regulator and squeezes off the air flow sooner. The unfortuate result is that the higher pressure required in the chamber to fire a ball at velocity makes this action less abrupt. The air flow is gradually reduced as opposed to shut off so some air escapes even after the ball has left the barrel of the gun. A more efficient design would be one that would use more of the pressure in the chamber as opposed to less. That way less air would be wasted after the ball has left the barrel. The only way I know how to do this is to reduce the spring tension. By doing this we would also have to reduce the air pressure in the chamber in order to reduce velocity and also prevent chopping. The size of the chamber limits this. It would have to be considerably larger.

Another way to increae efficiency would be to reduce the size of the chamber and keep the same springs we use now. This would result in less wasted air after the ball has exited the barrel. There is another thread about this somewhere.

[Magluvr]

Um...
According to that old thread, I think pbjosh mentioned two methods, either the higher pressure or keeping up the residual air in the chamber. It made sense to me. If instead of filling the chamber from 0 to 400 psi it would only be 100 to 400 say, resulting in less air having to be put in per shot, less air used per shot.

[athomas]

Its the leaking of air at the higher residual pressure that causes the mags inefficiency.

In that thread (if its the one I am thinking of) a higher pressure was considered while reducing the overall size of the chamber. The higher pressure compensates for the restriction. The smaller size allows the same energy to be released at the higher pressure. It also allows the chamber pressure to drop more quickly as the gun is fired. The result of this is a decrease in wasted air and thus increases the efficiency.

If you can keep the required chamber pressure to a minimum, and your air source at a maximum, you maximize your charge rate. The energy requirement is always going to be the same because it always takes approximately the same energy to fire a paintball no matter what gun is used. The main parts affecting energy are volume, pressure and time. If the volume stays constant then you must increase the pressure differential to decrease the charge time. If you have a fixed source, then you don't want to increase the residual pressure as it will result in less of a pressure differential.

You are correct in your assessment of the mag needing to get the bolt to recock sooner in order to increase efficiency. A shortened bolt cycle would mean that the volume of air to fire a ball would have been delivered quicker. Ideally, this time would be instantly, but we know that is not possible. So, keeping the air delivery time to a minimum is a major requirement for efficiency. By doing this we are using the air for acceleration of the ball rather than a cool breeze flowing out the barrel after the ball has left. Its the cool breeze that is the mag's major source of inefficiency.