Can’t get my velocity high enough

[brickout]

Here’s what I have:
Tippmann A5
E-grip
Flatline barrel
FVA mod
JCS RVA
Red Maddman spring (new)
Crossfire HP 68/4500 tank

Yesterday was my first time using my new HPA tank. Normally I run CO2, but since it’s getting colder I switched to HPA.

Now I know that the HP Crossfire tanks have an output of 800 psi and the A5 needs 850 psi. Unfortunately I found this out AFTER I bought the tank.

Well I figured that I should be able to get the velocity up high enough with the FVA mod, RVA all the way in and the brand new Red Maddman spring. Guess what…nope! I couldn’t get the velocity past 250 fps. As a matter of fact I had the RVA so far in the rear bolt wouldn’t reset every now and then.

I’ve run the exact same setup running CO2 and I’ve had no problems getting the velocity past 300 fps.

So do you think that I need to get the regulator on the tank changed to 850 psi? Will it really make a difference? I also talked to someone at the field that had the A5/flatline/HPA. He said that since I ran CO2 before that there is a possibility that I have a cracked powertube. Has anyone heard of that? I’ll have to check to see if it is cracked when I get home tonight.

[99GenX]

I'm going to give this a try...

brickout said:

Here’s what I have:
Tippmann A5
E-grip
Flatline barrel
FVA mod
JCS RVA
Red Maddman spring (new)
Crossfire HP 68/4500 tank

Nice setup!

brickout said:

Yesterday was my first time using my new HPA tank. Normally I run CO2, but since it’s getting colder I switched to HPA.

Good call!

brickout said:

Now I know that the HP Crossfire tanks have an output of 800 psi and the A5 needs 850 psi. Unfortunately I found this out AFTER I bought the tank.

Nope - A5's do not need 850PSI to run at 300fps... You can actually get them down to around 600-650 stock w/ a good RVA and a strong rear spring. The HPA tank will work great with the A5...

brickout said:

Well I figured that I should be able to get the velocity up high enough with the FVA mod, RVA all the way in and the brand new Red Maddman spring. Guess what…nope! I couldn’t get the velocity past 250 fps. As a matter of fact I had the RVA so far in the rear bolt wouldn’t reset every now and then.

Is it possible that you did not back out the FVA screw far enough? Doesn't sound right... Maybe the tank reg is having some problems with recharge, maybe something (teflon) has partially blocked an airway or is in you powertube?

brickout said:

I’ve run the exact same setup running CO2 and I’ve had no problems getting the velocity past 300 fps.

See above...

brickout said:

So do you think that I need to get the regulator on the tank changed to 850 psi? Will it really make a difference? I also talked to someone at the field that had the A5/flatline/HPA. He said that since I ran CO2 before that there is a possibility that I have a cracked powertube. Has anyone heard of that? I’ll have to check to see if it is cracked when I get home tonight.

I'd check out your internals and such for any blockage and whatnot - The tank should be fine.

Conclusion Sounds like a tricky one... First I'd check and make sure your tank has enough air in it. Secondly check your internals out along with any airways to make sure there is nothing clogging/obstructing them. If the gun looks fine, then your tank reg could be having some charging problems and any paintball shop should be able to find that out (if it's not anything but airing it up in another A5).

BTW Guys - Is it possible that with the FVA mod, RVA turned so high in, and the red spring, that he is putting too much pressure on the valve/powertube and not allowing it to be open long enough for sufficiant air?

[brickout]

The FVA was flush on the inside of the power tube last time I checked.

I know the tank had enough air. The guage on the tank was reading 4500 and the guage on the fill station was reading 4500.

I'm going to check the internals tonight.

[brickout]

I checked the internals, everthing clear and in good shape. The FVA is flush with the inside of the powetube as well.

[brickout]

So I take the tank to my local shop today to get the output checked. The tank is putting out 750 psi. The shop owner said that I still should be alright running 750. He said that the problem might be that I have a bad valve. He said that sometimes that it can appear visually that there is nothing wrong, but it's not working right.

So I give Tippmann a call...they said that they've never heard of such an issue and that I need a tank output of 850 psi.

I'm out of ideas.

[Gen]

I'd start over. Try putting the stock end cap back on it, screw the FVA in part way and check velocity. See if you can get it to 300fps that way. Then try it with your RVA. I know the problem I have with my RVA is that the shoulder inside that the spring rests on is actually about 3/8" further back when screwed in all the way. So I inserted about 3/4" of another main spring in there to bring the spring tension back up. Also, are you using really small paint? It might allow a lot of blowby that might be causing low velocity.

And about the 850psi thing, I know I've had mine down to about 600psi working reliably. They might just need to tell you that to be sure.

[brickout]

I think that's what I'm going to do. Go back to the begining and add the parts piece by piece.

I'll report back with my findings.

Hmmm, now where is there a chrono nearby.

[Electricity]

When i had my a-5, i used a crossfire tank, and had no problems with output.
Heres a question for you.
1 Have you cronoed with a different barrel?
2 have you sweetspoted your flatline?
From what i can remember, the prime FPS for the flatline was between 240 and 260 fps, not 300.
If i where you, i'd deffinatly look into sweetspoting your flatty, which basicly involves turning your rva all the way down so your running at like 200 fps, and slowly turn it up, as you shoot over a crono. When you reach the spot where the range is going back down instead of up, screw it back a bit, and you've got your sweetspot.
-E

[brickout]

Looks like my problem was paint-to-barrel size.

Here's what I did:
Ran the A5 on CO2
Stock barrel = fine
Lapco 12" bigshot = fine
Flatline = Fine <- RVA almost all the way in.

Ran the A5 on HPA:
Stock barrel = fine
Lapco 12" bigshot = fine
Flatline - could'nt get it past 255 fps.

So I belive the problem was what Gen had stated. The paint was too small for the barrel and the air was going around the ball.

[Wings]

If you get extreemly small bore paint you can run into the problem you mentioned with the flatline where to much air is escaping around it. Ideally a small-mid bore paint should be used.

Also remember that the flatline requires more air to operate. CO2 expands enough that its not really noticable. Make sure your not screwing in your HPA tank to far. I've seen people crank there CO2 tanks as tight as they can get em without a problem. Doing so with HPA will starve your marker. You want to put the tank on until the gas starts flowing and then no more than 1/4 to 1/2 turn further. Any more than that and the pin that depresses the valve will begin to restrict the airflow.

My setup is A5, flatline, palmer reg at 600psi, blue maddman, JCS rva. I sometimes have problems getting the velocity down to the flatlines nominal speed (about 275 for me).