RVA FAQ. Or, why you should buy an RVA!

[Kreeper X]

What is a Rear Velocity Adjuster and what does it do?

A Rear Velocity Adjuster (or RVA for short) is an aftermarket upgrade that allows you to by-pass the stock velocity adjuster and replace it with a more gas efficient and more consistant form of velocity control.

How is an RVA different than the Standard/stock velocity adjusters?

An RVA changes the velocity of the marker by increasing and decreasing the drive spring tension on the rear bolt of your marker. The FVA adjusts velocity by creating a bottleneck in the powertube, restricting the flow of gas from the valve to the powertube.

How does an RVA work? How about an FVA?

With the standard Tippmann bolt system, the Drive spring causes about the same amount of gas to flow throught the valve each time the marker fires. The velocity of the marker is controled by bottle-necking the gas flowing from the valve into the powertube by placing an obstruction in the way of the gas. This means that even though the velocity can change by use of the FVA, the amount of gas used is the same. Thus, you use as much gas to shoot a paintball to 250fps as you use to shoot one 300fps.

The addition of an RVA as well as the removal of the FVA obstruction in the powertube allows you to control the amount of gas pushed through the valve, and thus control velocity.

With and RVA, the tension on the drive spring is increased or reduce by the adjustment knob or bolt. When the spring tension is increased, the rear bolt has more potential energy as it's released by the sear, meaning that it hits the valve stem harder, holds the valve open longer, and requires more blow back gas to push the rear bolt back to the sear. This means that more gas is pushed through the valve and to the paintball, increasing velocity.

By reducing the spring tension, the real bolt has less potential energy, meaning it hits the valve with less force, holds the valve open for a shorter period of time, and requires less blow back gas to return the valve to the sear.

What are the advantages of the RVA over the FVA?

There are several advantages to the RVA set-up.

First of all, you have better gas efficiency and control. Since you're no longer using turbulance or bottle-necking to slow down the gas used in your marker, the gas hits the paintball with full force, thus it takes less gas to get the ball to speed.

Secondly, you get better consistancy. The removal of all the road blocks between the Valve and the Powertube and the fact that you're controling the propellant gasses more efficiently means that you're going to get better chrono results as far as consistancy goes.

Thirdly, RVAs allow for more precise adjustments of velocity. Some RVAs give you such fine tuning adjustments that you can get to about +/- 3fps and adjust it by 1 or 2 fps in either direction.

Are there any Drawbacks to RVAs?

Well, yes. There are a few.

The Increased tension on the drive spring can cause the rear bolt and sear to wear a little quicker.

With few exceptions, RVAs tend to prohibit you from using a stock with your marker.

Which RVA should I get?

It really depends on what you're looking for. There are two major RVA brands for the A-5, and those are the DOP RVA and the JCS RVA.

The DOP RVA

The DOP RVA is a simple replacement for your stock endcap which contains an adjustment knob use use to adjust velocity.

+ gives you all the perks from above.
- You cannot use a stock at all with the DOP RVA.
- Has a "less than effective" tourney lock, you can change velocity on the fly without tools
- The threads on the Knob are a little big, taking away some of the fine tuning ability of the DOP RVA.
- Built using a stock A-5 endcap.
- RVA component is held on by a C-clamp and has been know to "fly off" the marker leading to lost parts.

The JCS RVA

The JCS RVA is completely different than the DOP version. It's an endcap replacement, like the DOP, but it's made of machined aluminum.

+ All the Perks from above
+ Tourney Lock requires tools to adjust velocity as well as lock the velocity. No cheating at all.
+ The threads on the adjustment bolt are tiny, allowing for minute adjsutements to velocity to get it just right.
+ It's a tank. It's built from machined aluminum and no c-clamp.
+/- Only allows you to use JCS stocks. The JCS stocks are awesome though so it's not really a negative.
- Can take a LOT of adjusting to get velocity to move up or down in significant measures. 10 to 20 cranks to effect 7 to 15 fps.

[LilBigMan]

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