Originally posted by Rabies
A correctly working spool valve marker (except a shocker with the stock bolt) shouldn't be able to ramp velocity by varying the dwell. The dump should dump when the valve opens, and after that it shouldn't matter how long it's held open because no more air should be expelled.
Well, that's the theory.
In reality with most gun's the pressure chamber doesn't drop completely to zero. You don't dump all the air for a single shot, you just use the high pressure part of the air, but when the bolt comes back there is still pressure in the chamber.
You can see how this works in part when you dry fire as compared to shooting paint.
When you shoot paint your gun eats more gas and you get less shots. When you shoot paint, there is back pressure so the pressure in the dump chamber stays higher and you get better efficiency.
ABS works because it keeps the chamber open and allows you to use more of the air in the chamber. It uses more of the energy on the air to get over 'stiction' (static friction which causes first shot drop off).
You can absolutely change velocity based upon the dwell and how you release the air, depending on how the gun is set up.
Originally posted by John C
The Ton Ton shocker board has something called ADOC, automatic drop off control.
If it really does, and they admit that, then ban them right now. It's adjusting the dwell and that is not allowed without tools because it adjusts velocity. You are NOT allowed to adjust velocity on the field. If the board is doing that and they admit it, it's simple to ban them all and all the boards. If they are using that as a selling feature, ban all boards and guns using it.
Many guns do experience slight drop off under high rates of fire, but measuring it and compensating for it is phenomenally bull****. And what if that gun doesn't experience the same drop off? The only way to compensate is to 'overcompensate'. Often guns become more inconsistent at higher rof, not necessarily drop off, you get ups and downs as the regs try to work.
I despise velocity ramping. Some guns are definitely easier to do it with that others.
Lots of spool valve type guns have problems with 'stiction' and thus get FSDO. I don't believe ABS or similar should be allowed. Deal with maintaining your gun or accept it has inherent design flaws. Don't break the rules to get around a design problem.
I believe under the rules it also becomes 'changing the velocity on the field'.
I'm inclined to let ABS slide as long as it isn't horrific in when it comes in and how much it increases the dwell by.
But adjusting the dwell on the fly as you increase ROF should always be illegal. Jim Drew is the guy that initially tried to implement that, then Freeflow with the Anderson board. We should fight against anyone that does it.
If a gun is maintained and designed well drop off under high rates of fire is not a valid issue or excuse for adjusting the velocity as you shoot.
