Automag Efficiency: New Springs?

[nak81783]

First, I'm not too worried about efficiency. I can shoot all the paint I carry, so I just fill up on air when I reload on paint. However, others may have different situations that need every bit of efficiency possible.

Second, this probably doesn't apply to Classic Valves. Since regulated air is used to reset the trigger, lowering the operating pressure would likely cause slow trigger resets, short-stroking, etc.

That said, if one were to accept lower cycling rates from an RT/X-Valve, say 12bps, instead of 26+, could the regulator springs, reg piston assembly, reg pin assembly, and bolt spring be reconfigured to operate at lower working pressures, increasing efficiency? This shouldn't change trigger performance, since it's still input pressure resetting the trigger. Pressure/volume to fire a paintball at normal play velocities doesn't change, but the pressure required to cycle the marker would be reduced.

Thoughts?

[BigEvil]

You should never have to change a reg spring....
The efficiency would be determined by a few things... the force of the main spring holding the bolt back.. and the diameter of the power piston inside the bolt. IF you increase the amount of area that pressure is acting on, it should theoretically require less pressure to move.

[going_home]

I carry 1k on the field and can shoot it with my Xvalve'd mags no problem.

More than that in one game is 1) too much weight around the waist 2) too much money spent for one game.

[blackdeath1k]

2) too much money spent for one game.

Depends how long said game last. Just a thought.

I carry 7 pods and a hopper on the field during scenarios. That's what I can get out of my tank when full so that is what I carry.

[nak81783]

You should never have to change a reg spring....
The efficiency would be determined by a few things... the force of the main spring holding the bolt back.. and the diameter of the power piston inside the bolt. IF you increase the amount of area that pressure is acting on, it should theoretically require less pressure to move.

But don't the reg springs dictate the pressure at which the reg seat seals? If you increase bolt surface area or reduce bolt spring force without reducing pressure, won't you have dangerous velocities?

I was just hoping that springs and bellvue washers could be easily changed without redesigning anything. Once a lower, more efficient working pressure was found, the reg piston assembly could be recalibrated to vent at the new pressure that would cause excessive velocities.

[athomas]

Think of a level 10 mag. You increase the spring tension to make it easier on paint when operating at 300fps and sacrifice a bit of efficiency. If you reduce the spring tension, you will make it harder on paint at 300fps, but should gain some efficiency.

The regulator can go down to quite a low pressure. The normal operating chamber pressure of a level 7 mag is about 350psi. The regulator can go quite a bit lower than that such that you can get 170 fps shots. I don't know what the chamber pressure would be at that range, but I suspect it would be quite low. So, the regulator shouldn't be a problem in its current configuration.

If you do use a lighter bolt spring, you can reduce the operating pressure of the mag. A few things will happen. The ball will get hit harder when a shot occurs. The power impulse will be more abrupt. More low pressure air will dump from the chamber during each shot. That is a good thing for efficiency, especially since the power impulse would keep the bolt fully forward for more efficient acceleration of the ball. The bolt hitting the ball harder is a bad thing, because it does that at a higher speed. This can also damage the next ball in the stack. If you lighten the spring too much, then the reset becomes an issue as well. As it is now, the biggest resistence in the reset is the residual air in the chamber. If you operate at a lower pressure, then the friction forces and the mass of the bolt become a larger percentage of the return force needed. They are not as consistent and can change depending on dirt or maintenance activities which could affect the springs effect on the bolt mass.

It can be investigated. I've often wondered about this too, just for curiosity.

[nak81783]

If you lighten the spring too much, then the reset becomes an issue as well. As it is now, the biggest resistence in the reset is the residual air in the chamber. If you operate at a lower pressure, then the friction forces and the mass of the bolt become a larger percentage of the return force needed. They are not as consistent and can change depending on dirt or maintenance activities which could affect the springs effect on the bolt mass.

This was my concern, and if anything less than a gold spring won't reliably reset the marker, this all goes out the window.

As far as the rest of your post, it was exactly the functioning of the Level 10 that made me consider this. It's all a balancing act, but the one thing I don't recall ever being considered is slowing down the bps of the valve. As it is now (again, I'm only talking RT/X-Valves), the bolt's forward and rearward speeds are such that the resultant bps is much higher than most fields allow. 10-ish bps seems to be the current norm, so I figure 12bps would give some safety factor, such that the marker isn't right on the edge of not firing. Good to know the reg can be set that low; thanks. So, if there is a lighter bolt spring that would reliably reset the marker, wouldn't lower pressure result in: 1) a slower forward moving bolt? 2) a longer "sealed dwell" to efficiently use the dump chamber? By "sealed dwell", I simply mean the on/off is closed, so the marker isn't just dwelling with the entire system open, wasting air. It's still a balancing act between operating pressure and bolt spring return, but the whole act would be at lower pressures, making it more efficient.

So where can I get appropriately sized square wire springs with lower spring coefficients?

Edit: It looks like the springs need to be between 6-7 coils, so as not to significantly change the location of the bolt when it's at full forward position. That's assuming the spring gets fully compressed when the marker fires. I assume it must, since the gold, red, and silver springs I have (multiples of each) all have 6-7 coils; the pitch is just slower on the longer springs. Is the spring coefficient constant on the gold, red, and silver springs? The extra force comes from having to compress the longer springs more?

[athomas]

The bolt will probably move ahead faster than before, even at the lower pressure. Because of the bolt dumping more air, more quickly, it would probably start its return in less time as well. Theoretically it should move back faster too, because of having less air remaining in the dump chamber. The unknown is the friction component and inertia forces due to the mass of the bolt. All the theory might go out the window if they have too much affect.

I think you can get away with a lighter bolt spring, if you are willing to put up with higher impact on the ball. How much lighter of a spring will have to be investigated.

[Laku]

So beside spring how could the bolt acceleration be gradually increased so that the first contact with the ball would be softer? I don't see a way to do that with the current configuration.

Also with lower pressure, wouldn't you need larger chamber volume?

[nak81783]

So beside spring how could the bolt acceleration be gradually increased so that the first contact with the ball would be softer? I don't see a way to do that with the current configuration.

Neither do I.

Also with lower pressure, wouldn't you need larger chamber volume?

I don't think so. As athomas points out, there is residual pressure in the dump chamber, so it's not at the point of starving the shot yet. I'm assuming this means, once the paintball is already up to speed, and the bolt hasn't yet resealed, it is simply wasting air. The air released during this time is neither accelerating the ball or remaining in the dump chamber for the next shot. I'm just trying to figure out a way to get it closer to that point of starving out the shot, at the cost of (in my opinion, unnecessary) rate of fire.

But without knowing what springs are quickly and inexpensively available, not being able to adjust surface area of the bolt stem, etc., I'm not sure how successful this endeavor would be.

[nak81783]

Back to this again.

Refresh my memory on why the bolt springs are square wire. Anti-bind? Anti-twist?

Am I going to tear up my ULE body if I use more readily available round wire springs? Im thinking I should buy a surplus steel body for testing.

[athomas]

Square or rectangular spring wire is often used in situations where more precision is required. You get more spring metal in the same physical compression distance. This allows a better spring constant. The square edge allows better stability, especially when the spring is fully compressing. A round edge could cause some deflection when the spring compresses against itself.

[vintage]

if you have ever had a 1911 handgun you can see the defection of round springs when you are putting the main spring plug back in after cleaning.

[nak81783]

Good point.

[nak81783]

I contacted Tim (Sandman) about this topic, hoping to get AGD's bolt spring supplier. AGD worked on this numerous times over the years. He basically confirmed what athomas said above. The bolt would need to be lighter due to force required to move the current bolt forward and backward. I won't deceive myself that this would be a simple endeavor, and I'll be honest that I have neither the time or desire (due to efficiency not being a concern to me, plus the personal financial expense) to pursue it.