Spring Tuning

[The Dawg]

Does anyone cut there own springs? I know AGD sells the grey ones to be cut down, but I never hear anyone talk about doing it. I am considering trying it because its relatively cheap and lets me fiddle with my mags more. What is the ultimate goal of grinding your own spring? How do I know when I'm done? Does it make the gun more gentle on paint? I got a Tac-One recently (first x valve) and it breaking more than any classic I've ever owned.

[Laku]

Does anyone cut there own springs? I know AGD sells the grey ones to be cut down, but I never hear anyone talk about doing it. I am considering trying it because its relatively cheap and lets me fiddle with my mags more. What is the ultimate goal of grinding your own spring? How do I know when I'm done? Does it make the gun more gentle on paint? I got a Tac-One recently (first x valve) and it breaking more than any classic I've ever owned.

Like you guessed the ultimate goal is to get it as gentle as can for the paint, in the velocity range you are using. Are you using force feed/electric hopper on your Tac? Using gravity feed will cause more chops, specially if your lvl 10 isn't properly tuned.

[Nobody]

All the spring does is reset the bolt. It does nothing towards how gentle it could be on the paint, that is the L10 kit.

[Spider-TW]

All the spring does is reset the bolt. It does nothing towards how gentle it could be on the paint, that is the L10 kit.

The longer springs counter-balance of the pressure force on the bolt stem. That's why longer springs are more gentle on paint for a given velocity and the bolt will not fire reliably on the level 10 at lower velocities with longer springs.

Agreed that it doesn't really matter too much on a level 7, except stronger springs mean that the bolt moves slower and bolt dwell goes up.

There is a pretty fair range where bolt springs work well enough, relative to being easy on paint. You shouldn't need much to get in the workable neighborhood of 3/16" beyond the tip of the bolt, - 1/16",+1/8". On a new Tac one body, you should check your paint versus the detent and make sure you're not double feeding and that you still have your foamie if you are using a force feeder.

Last weekend we had some 0.672" paint, which is very uncommon around here. Even my custom 0.675 and 0.680 barrels/inserts were getting rollouts. I resorted to my RT with a J&J twistlock barrel and a good detent and called it "overbore". I have lots of barrels and kits, but my best solution was an old mag with a twistlock.

[athomas]

Are your paint breaks caused by chops or barrel breaks? They are two different things. A level 10 will prevent chops, but not barrel breaks. A large enough barrel id and good working detents are key to preventing barrel breaks.

If you want to tune your level 10 bolt spring for optimum softness, that is great, but it really is only needed on really brittle paint.

For spring adjustment:

You want to use the bolt spring that allows you to shoot about 20fps above the lowest velocity that the gun will cycle at. So, if you want to use the gun at 280fps, then your desired lower limit of operation is 260fps. Insert your long bolt spring. Turn the velocity adjuster down before you air up the valve. Then gradually turn up the velocity until the gun will cycle. This is your lower velocity. Measure it. If it is above 265fps, then you will need a shorter spring or you will need to clip the one you have (unless you have red one. They are usually in the correct range). If you clip a spring, only clip half a coil at a time and then try it using the same procedure of starting with a low velocity setting. Make sure you put the cut end of the spring towards the bolt. If you have the short spring installed, and the lower range is 30fps below the desired shooting velocity, I wouldn't worry about using a stiffer spring and would just go with the short bolt spring. If it was much lower than that, I would definately clip a long spring to get closer to the desired range.

[Cyco-Dude]

yeah, i have a minimag with a cut gray spring. it's tuned to be as soft as possible while still being able to feed a paintball into an underbored barrel. the goal is to be more gentle on paint. even with a reset (and gold spring), it's possible to crack the shell of a paintball, which results in a barrel break on the next shot.


All the spring does is reset the bolt. It does nothing towards how gentle it could be on the paint, that is the L10 kit.
you are mistaken. the spring resists the forward movement of the bolt, therefore the more resistance (stronger the spring) the slower the bolt moves forward, which means more gentle on paint. the level 10 kit for all of this is understood.

[cockerpunk]

All the spring does is reset the bolt. It does nothing towards how gentle it could be on the paint, that is the L10 kit.

oh but it does. the longer/stiffer springs are more gentle on paint.

[kfletch]

So when you increase the resistance (longer spring), and increase velocity (higher psi going to chamber), aren't you A. Back where you started, and B. Getting less shots out of your tank due to the increased psi. being expended?

[Cyco-Dude]

So when you increase the resistance (longer spring), and increase velocity (higher psi going to chamber), aren't you A. Back where you started, and B. Getting less shots out of your tank due to the increased psi. being expended?
no...while you do have to increase the pressure a bit, that doesn't mean the bolt then moves forward at the same velocity that it did with the weaker spring and lower pressure. those two things don't change in a linear fashion, otherwise there would be no point in spring tuning. this is easy to see for yourself if you have a 'mag with a lvl 10 bolt, some springs, and your finger. put the gold spring in, chrono to 280, insert finger and pull the trigger. now try it with the red spring (or cut gray spring), also chrono'd at 280. you will feel the difference right away.

less shots out of your tank...it really doesn't matter, does it? how many more do you think you'ld get with a weaker spring? is it worth a barrel break if the bolt pinches a ball and cracks the shell? tanks are big enough, air is free...it's a non-issue as far as i'm concerned.

[kfletch]

Ok I didn't want to get all scientific but, your theory defies the laws of physics. Translational kenetic energy is factored by 2 things, mass of the object and speed of the object. You can't tell me you can propel a paintball 280fps with a bolt moving slower than the same bolt moving faster.

[kfletch]

And yes in fairness I'll try you theory out this weekend. Because I've never needed or been suggested by anyone on here otherwise, to use anything other than the gold spring. Works perfect with a correctly tuned level 10.

[kfletch]

Why do I feel a joke about air speed velocity and a certain Swallow would be perfect here?

[athomas]

Ok I didn't want to get all scientific but, your theory defies the laws of physics. Translational kenetic energy is factored by 2 things, mass of the object and speed of the object. You can't tell me you can propel a paintball 280fps with a bolt moving slower than the same bolt moving faster.The bolt speed doesn't have much effect on the velocity of the ball. The air released from the chamber does.

In theory, we should just be able to insert a stiffer spring to slow the bolt and lessen the impact on the paint without affecting the velocity. However, the bolt spring also causes the bolt stem to act like a regulator and restrict the air movement. This restriction of the air reduces its ability to accelerate the ball as effectively so the velocity is reduced. The pressure needs to be increased just to get back to the original set velocity. The ratio between chamber pressure and velocity is different than the relationship between chamber pressure and forward bolt force. This causes the pressure adjustment to increase the velocity at a rate different than the increase in the forward bolt force, so even though the pressure and velocity is higher with a stiffer spring, you never get back to the same velocity/differential force combination as with the lighter spring. The regulator effect of the bolt stem slowing the air release causes some wasted air that follows the ball out the barrel without actually causing any acceleration, which is why the level 10 bolt setup is not as efficient as a level 7 bolt.

[Cyco-Dude]

The bolt speed doesn't have much effect on the velocity of the ball. The air released from the chamber does.
winner winner, chicken dinner.


And yes in fairness I'll try you theory out this weekend.
no theory; it's fact. gold springs work ok, but can still hit hard enough to crack the shell of more brittle paint during a mis-feed.

[kfletch]

Oh so now it's air that propels the balls, no need for foamies then. Please explain low pressure paintball guns then? Are we to believe they figured how to propel a paintball with 300 psi the same distance as ones operating at over 1000? No its math people.

KE=.5×M×V□

They achieve this by lowering the mass and increasing the speed. It's the only way to achieve the same KE.

[Laku]

Oh so now it's air that propels the balls, no need for foamies then. Please explain low pressure paintball guns then? Are we to believe they figured how to propel a paintball with 300 psi the same distance as ones operating at over 1000? No its math people.

KE=.5×M×V□

They achieve this by lowering the mass and increasing the speed. It's the only way to achieve the same KE.

Really?

Foamie is there to prevent a ball rolling back and allow the next ball in stack to drop partially in which leads to chop. Also cushions the bolt tip a little.

Bolt movement only pushes the ball into the barrel, it's the air that launches it. You really need to brush up your understanding on paintball gun working principles.

Hint. Higher pressure short burst vs lower pressure longer burst. And mag doesn't use the same pressure that is input to fire the ball. As I recall it's around 450psi that launches the ball (someone correct me if I'm wrong).

[2BAD4U]

:cheers: :goodjob:

[kfletch]

You are correct it doesn't use the same pressure that is inputed, but neither does low pressure paintball guns. The Dye NT uses around 150 psi in its chamber to launch a paintball. No one has yet to explain if the bolt has little effect in launching a ball how low pressure guns achieve the same fps as high....but I'm done. Shoot your guns as you like. As for Dawgs original question, I've been shooting 20 years with gold springs and have had no reason to change.

[blackdeath1k]

You are correct it doesn't use the same pressure that is inputed, but neither does low pressure paintball guns. The Dye NT uses around 150 psi in its chamber to launch a paintball. No one has yet to explain if the bolt has little effect in launching a ball how low pressure guns achieve the same fps as high....but I'm done. Shoot your guns as you like. As for Dawgs original question, I've been shooting 20 years with gold springs and have had no reason to change.

Actually laku did answer. LP HV or HP LV. Really simple. Same principle works with electricity. Higher the voltage the lower amperage needed. Lower the voltage higher amperage needed.

[Laku]

Off topic, but here's a really good video where you can see the bolt speed in slow motion and the point where the air chamber is opened and the air starts to propel the ball forward as it accelerates. This is from PE Ego, so low pressure high volume.

https://www.youtube.com/watch?v=WXM6MpEsalA

[athomas]

If you measure the actual pressure behind the ball as it starts to accelerate, you will find that all paintball guns operate at approximately the same pressure. The restriction in how the bolt delivers the air determines how much chamber pressure is required to deliver the required pressure behind the ball.

The ideal paintball gun would deliver exactly the required pressure to the ball instantaneously. The air impulse would be perfect and ideal. It would use the least amount of air for any given velocity. As soon as you add a restriction to the air path, you need to increase the chamber pressure to maintain the proper air pressure behind the ball. You could still have near ideal conditions if you could shut the air off instantaneously once the ball was properly accelerated. A smaller chamber would help here. This is the premise of high volume, low pressure or low volume, high pressure.

The "low pressure" guns open the chamber completely and hold it open using a piston that is not affected by the air in the chamber. The chamber can effectively dump all the air at once, creating a nice instantaneous air pulse. A "high pressure" gun like the mag uses the chamber air to hold the bolt open. Since the spring is holding back against it, the bolt stem acts like a regulator and restricts the air flow. The air impulse in this case starts fast but trails off as the air is depleted. There is always a significant amount of residual air left in the chamber after a shot is fired by a mag. Since it takes more force to push the air past the restriction it requires higher chamber pressure just to maintain the required pressure behind the ball. In both cases, the pressure to actually fire the ball is essentially the same.

[athomas]

I always had issues with that Planet Equlipse video. It illustrates a problem that exists, but they didn't compare apples to apples when showing the problem and their solution using paint. The first yellow paint bulges and deforms when pushed into the chamber. It is that bad. The second orange paint is much stiffer and stays round.

[kfletch]

Yeah but it is a great example that the bolt does lititle in the acceleration of the paintball and the air does most of the work. I wouldn't have believed it without seeing it myself. I stand corrected.

[The Dawg]

I'm a little proud i started this thread. Not only am I learning quite a bit, I'm also very entertained. Thanks for the info all.