exactly how IMPORTANT are shims?

[cwuchu]

In tuning my lvl 10 that I just received, I noticed that the mod works the same with different numbers of shims in the powertube. Are the number of shims important to how well the lvl 10 works? I think it might from logical reasoning:
1. If there are very little to no shims in the pt, venting will occur later in the firing stage (very little later since the shims are very thin) thus when the gun is shot, the bolt is moving full speed for the first few milliseconds after the sear releases the bolt - before venting occurs.
2. If there are many shims in the pt (not so many that it leaks constantly), the venting will occur right after the bolt is released and thus provide an immediate reduction in the speed of the bolt.

Should you have as many shims as possible in the pt, but not so many that it leaks - so the bolt will be soft all the way through the first stage? How many shims will make a very effective lvl 10 possible?

[TransMan]

Everyones set up will be dif you have to play around with yours to get the best results im usin 2 shims in mine. I tried 4 but had constant vent so i stuck with 2 im gonna try 3 a little later

[BlackVCG]

Shims are not all that important in the process of tuning the LVL 10. They're a part of the kit because they provide room to adjust for tolerance differences and paint size.

If the bolt is going to pinch a ball and it's able to vent, it's going to vent at the same point regardless of how many shims it has. So basically, get 2-3 shims in there and as long as it doesn't leak and it doesn't lock up on a ball when it pinches it, it's fine.