Inconsistant Chrono

[chadlh]

I was wondering what sort of range I should be expecting when checking FPS with a chrono. It seem I'm all over the place. First shot usually in the 280 and than if I have additional shots right after I'm all over under 300fps.

My marker:
RT Pro Rail
PF Left
Emag Valve
Intelliframe
Stock on/off (still messing around with my ULT)
LX

Pure Energy 72/3000

I'm thinking that it's probably the stock pure energy regulator. Would that be a safe guess?? What else should I be looking at?

Thanks for your help

[maglover728]

What do you mean "all over under 300?" Like 299, 155, 263,198,300,289,147? How wild are the readings?

[chadlh]

Readings are down to like 220's and up to high 290's. The majority of them are between the 260's to 290's though.

I understand that there are factors like paint to barrel match but I still wouldn't think that these numbers would bounce around that much with a somewht reasonable match.

[egb groupie]

Make sure your valve is well oiled. Also check the condition of your reg piston o-ring. To do this, unscrew the velocity nut (where you adjust the velocity in the back) all the way out till it falls out. You will see 2 springs sitting on the inside of the nut, leave them where they are at. if you look on the inside of the valve, you will see a small cylindrical shaped object. This is your reg piston. Gently tap the back of your valve into your hand or onto a table covered with a towel or something until it falls out. You will see a small o-ring at the smaller end of it. If this looks dried out and cracked, replace it. If its just really dry, lube it up well with some paintball oil. , Reassemble the valve, taking care to get the pin back inside the hole of the reg piston where it came out of. Screw the velocity nut back on, springs included, to approximately where you think it was before, and rechrono. Hopefully that will solve your problem.

[chadlh]

Checked the o'ring you suggested and all is good. I'm guessing it is just the tank regulator since I've heard that they do have a problem with that. Guess my next purchase will be a new adjustable tank regulator.

[Badmovies.org]

Are you familiar with tuning your Lvl 10 bolt? Quite often, I have found that people use too small of a carrier. It does not leak, but their velocity is all over the place.

Tunaman taught me a neat trick that works when trying to help someone check if they have the right carrier:

Oil your o-ring, put it into the 2.0 carrier (2 lines, no dots), slide it onto the bolt stem and attempt to dangle the bolt. (You are holding the carrier while trying this.) If the bolt slips off the carrier from its own weight, go to a smaller carrier. Use the largest carrier that will not allow the bolt to slip off using this test. Do not add any shims yet. Oil everything, assemble, and break in the o-ring by shooting out a tank of air. After doing this, you may need to change carriers and use the next smallest. Now, start adding shims one at a time until it leaks down the barrel. Take the shim out. You are now ready to go.

With a correctly sized carrier, I find that I usually have 2 or 3 shims.

[athomas]

I never use carrier shims.

Don't worry about the tank reg yet. A poor one can cause shootdown during long strings of shots, but shouldn't cause an increase in velocity in a mag. A mag has its own regulator built in which removes any spikes in pressure from a tank reg.

The first place I would check for problems is in the quality of the paint. Inconsistent paint can cause velocity fluctuations. Make sure there is no oil or grease on the outside of the bolt or on the bolt spring. Residue transfers to the inside of the barrel. As mentioned, check your carrier size. Do this with no powertube shims installed. Clean the valve. A single piece of dirt in the mag regulator can cause velocity fluctuations.

[egb groupie]

In addition, I would listen to it very closely while it is gassed up, I know I've had ever so slight leaks that I could only hear if I had my ear right up next to it. Another cause that I have found that could cause slight variations in velocity is the trigger pull. The more consistent you are in the release, the more consistent in the chrono. Not saying this is the one thing causing it, but it could be a contributing factor...

[pierce]

I'm going to agree with Badmovies a say your carrier is too small.

[PhoenixWolf]

I've found that tank is VERY inconsistent. It really makes a mess of your chrono speeds. A good tank like a MacDev or any of several other brands will give you much tighter chrono speeds. Additionally, if your gun is new, your regulator hasn't broken in yet. Both the gun and the tank's regulators need to break in before it gets consistent. After a case of paint, it should break in and become very consistent. Every time you refurbish your regulator (replace the valve's O-Rings), it needs to break in again.

[braaatz]

I will get inconsistent readings if I dont follow the correct procedure to chronograph an
RT/Emag valve.

Heres the Procedure I copied from the RT manual:

To record your highest rapid fire velocity: Fire a paintball and hold
the trigger back. Then release the trigger completely and fire the
next paintball as quickly as possible, once again holding the trigger
back. Repeat as necessary. This procedure will simulate rapid fire,
thus recording your highest possible rapid fire velocity.