Leak - comes and goes as it pleases?

[Ando]

Not sure what you mean by this, but I don't think removing a component that is reccommended in almost all setups to be a "finely tuned" valve nor a "generic" one..

You hit it right on the nose. "In almost all setups" which again is a blank statement. In your case, it's screwing your setup up. So what would you call that?

All I'm saying is if you have more then one person giving you marching orders and no ones yelling "STOP IT'S A TRAP!!!" Then take the persons word for it. Thomas explained quite well what was going on but you insisted it was something else causing the problem.

And BTW...The shims do nothing for the sensitivity of the lvl 10. It's actually your bolt spring that governs that.

[ProFalcon]

The shims do nothing for the sensitivity of the lvl 10. It's actually your bolt spring that governs that.

Thank you, that was what I wanted to know.

So is it just minor manufacturing tolerances that affect how many shims you need? And the function of the shims is to adjust where the carrier 'floats' to allow for it to still seal with the stem, regardless of the variances in location of the vent hole?

[athomas]

The shims have no effect on sensitivity. The level 10 sensitivity is solely affected by the bolt spring and the chamber pressure. The difference in force between the bolt spring pushing the bolt back and the air pressure pushing the bolt forward is the force that is applied by the bolt on the ball. For a given barrel length (which changes the amount of pressure it takes to reach a certain velocity) and a given bolt spring, the sensitivity varies with the chamber pressure which also changes the velocity.

The optimum tuning of a level 10 bolt involves reducing the amount of friction to a value as low as you can get. That means having the inner carrier oring as loose on the bolt stem as you can. If the carrier is too large, the oring is not tight enough and the oring does not seal against the bolt stem. This causes a leak. If the carrier is too small, the oring is too tight against the bolt stem and the friction increases. Too much friction force when subtracted from the differential force of the spring force and air force can result in the bolt not moving freely enough. This manifests itself as bolt stick. It can happen in the forward direction where the bolt doesn't move forward properly, or in the reverse direction where the gun fires and then doesn't reset properly.

Shims are the most misunderstood concept in the level 10 tuning program. The basic operation of the level 10 does not involve any shims at all. They are not needed and provide no function to the sensitivity or to the ability of the level 10 mag to fire a shot. They only adjust how far the bolt needs to move in the event that there is a blockage directly in front of the bolt that allows the bolt lip to move past the sear catch, but not far enough to expose the level 10 vent hole. The thickness of a level 10 shim is 0.01". Two shims is only 0.02". If there is a blockage, the bolt will almost always move far enough to vent air even without any shims installed. If the gun misfires, chuffs, coughs, sticks after a shot, or vents air in any way, then adding shims will not help because the vent hole has already been exposed, and that is what shims do (shorten the distance required to expose the vent hole). If it takes the addition of shims to get a level 10 mag to fire, you need to ask the question of what is causing it to stick, rather than how to compensate for it.

Quite often shims are added at the beginning of a tuning project and then the carrier size is adjusted to find the proper carrier oring tension. Relaxing the tension of the oring can make the sealing surface of the oring narrower. If the oring is close to the edge of the vent hole, then making the sealing surface narrower can cause some of the oring sealing surface to cross the edge of the vent hole which results in a leak. A lot of people incorrectly use a tighter carrier size to tighten the oring which results in a wider sealing surface and closes off the leaking edge at the vent hole. The wider sealing surface and increased tension also increases the friction and can cause other random firing issues due to bolt stick or even more leaking. The bolt can leak if the carrier is too tight and causes the assembly to get pushed back by the bolt stem. The vent hole remains exposed and the valve leaks continuously out the front, even with a tight carrier setup and the shortest bolt spring, even though the gun will cycle without sticking.

The original level 10 tuning guide and a few others early in the level 10 life incorrectly suggested that sensitivity could be adjusted using carrier oring tension and shims. That was quickly found out to be not true which is evident in the 2100 posts in the level 10 Problems thread here.

[athomas]

So is it just minor manufacturing tolerances that affect how many shims you need? And the function of the shims is to adjust where the carrier 'floats' to allow for it to still seal with the stem, regardless of the variances in location of the vent hole?

The shims prevent it from floating too far forward.

It is hard to manufacture anything with tolerances so tight that every part fits perfectly. We could, but the cost would be so high, that we couldn't afford the purchase price. If each part was off just a couple of thousands of an inch, the total error adds up to quite a bit. Having the shims gives the option to make an adjustment if it is needed. 99.99% of the time it is never needed even in the most extreme cases.

[ProFalcon]

Ahh, Thank you. That big post makes a lot of sense.

When I received the mag and it was leaking, I moved to a smaller carrier, which puts more friction on the bolt stem, which can actually lead to it not fully resetting, causing occasional leaks when shooting. If I were to remove the shims, the carrier would settle farther forward on the bolt stem and would possible enable me to move up a carrier size, further ensuring that the vent hole is behind the carrier seal when at rest every time.

Not sure what the guy before me was doing with it... probably why I got a good deal on it, lol.

The articles I read on how to originally tune and setup your mag is extremely misleading. They completely misrepresent the function of the shim.

Once I remove the shims and retune the carrier, how is best to proceed with springs? How does one determine which spring to use?

[athomas]

The ideal spring allows you to shoot about 20fps above the lowest velocity that the valve cycles at. If you want to shoot at 280fps, you want the gun to start shooting at around 260fps. So, start with the red spring if you have one. With the velocity turned down, gradually increase it until the gun starts to cycle. Measure the velocity. If it is around 20 fps below where you want to shoot, you have the proper spring. If the velocity is quite a bit more than 20fps below where you want to shoot, then install the long grey spring and try again. The longest grey spring usually puts you above 300fps, but you can cut it back to get it in the proper range. Only cut one end of the bolt spring. You need to have the uncut end against the front of the body and the cut end against the bolt. Cut the spring at the rate of 1/4 or 1/2 a coil at a time. You will get a feel for how much velocity each coil represents as you cut and measure. Cut the spring until you achieve the velocity range that you want the gun to operate at. If you want to operate at 290fps, cut the bolt spring down so that the gun starts cycling at 270fps. Then adjust the velocity up to 290 and you will get great anti-chop capability and consistent operation.

The short gold spring is the all purpose spring and operates at most velocities. It usually allows the gun to start cycling down around 200fps.

The red spring is the middle spring and usually operates at around 280fps depending on the barrel setup you have. The newer kits don't come with a red spring so you need to cut down a grey spring if there isn't a red one.

The long grey spring is the stiffest one in the kit and usually starts most mags cycling at a velocity above 300fps. It does allow you to cut it down and precisely tune the bolt for optimum performance.