Page 1 of 2

legitimate count per second

Posted: Tue Apr 03, 2007 5:57 pm
by richardbridges
What do you think is the most legitimate way to find your rate of fire? Use a stopwatch on a preallotted amount of bbs, say 100, 1000, or 10,000. Then divide the rounds by the seconds it takes to fire them, or does anyone have a better idea?

Posted: Tue Apr 03, 2007 5:59 pm
by benstern
mechanical trigger device. Have a machine pull the blowgun trigger and release it after exactly 3 seconds. Count the bbs.

Posted: Tue Apr 03, 2007 6:03 pm
by richardbridges
Why 3 seconds? Wouldn't a longer timeframe give you a more accurate count?

Posted: Tue Apr 03, 2007 6:23 pm
by BC Pneumatics
Considering the semi-erratic firring of te BBMGs, I just fully load it, and time it until it is empty. (Well, until it no longer produces a healthy stream.)

Posted: Tue Apr 03, 2007 6:23 pm
by noname
Longer bursts lowers ROF, so it wouldn't really be accurate any way you did it, but I'm planning on using 500 BBs, measured by a stopwatch.

Posted: Tue Apr 03, 2007 6:27 pm
by BC Pneumatics
I fire in longer burst, so why the hell wouldn't I measure that? (Also, my gun doesn't slow down during longer bursts, just when it is near empty.)

Posted: Tue Apr 03, 2007 6:45 pm
by noname
You can measure longer bursts, but they won't have the same ROF as short bursts. Any strafer will slow down (unless it's electrically fed and fired) in a longer burst than in a quick squeeze on the trigger, it's just not visible, because it slows down by 15 or 20 per second.

Posted: Tue Apr 03, 2007 6:49 pm
by BC Pneumatics
I'm not going by my eyes, they aren't that good. In my experience, measuring short bursts compared to long bursts only improves accuracy, and there is nothing close to a 20 RPS difference on my gun.

What would possibly possess you to proclaim "Any strafer will slow down (unless it's electrically fed and fired)" ?


Edit: I forgot to mention that I attributed the differences between large burst and short burst tests to the short 'rev up' required before the gun fires at full capacity. (The short bursts actually tested a little 'slower')

Posted: Tue Apr 03, 2007 6:55 pm
by noname
I said because it's true. An electric gun that feeds, fires, and repeats the process will have a steady ROF the whole time, whereas an air powered gun needs to feed, fire, get more air to the hose, get more air to the tank, and still put out air while this is all happening, thus changing ROF. A short burst will have a better ROF because the BBs are loaded and ready, the air tank is full, the hose is fully pressurized, and the valve is ready to dump air. A longer burst has to continuously do everything I said an air powered strafer needs.

Posted: Tue Apr 03, 2007 7:14 pm
by BC Pneumatics
True? No, Conditional.
Forget the electronics, that is not what we are talking about (I guess I should have left it out of the quote to avoid confusion)

In the conditions of my firing, there was not significant latency in air supply to cause a drop in firing rate. Sure, the first 1/2-1 second is bumpy, but anything after that is constant.
A short burst will have a better ROF because the BBs are loaded and ready
Actually, in the design of a typical BBMG from these forums, the BB's aren't 'ready' until they are in motion, so I guess this would be a point in the opposite direction you are arguing for. Thank you for bringing it to my attention.
the air tank is full,
And if using a tank that doesn't drop significantly in pressure? Like, say, I dunno, a 20ish gallon tank fed by a compressor and a 20lb CO2 tank?
the hose is fully pressurized
I am considering this part of the 'tank system'
the valve is ready to dump air
This isn't a factor. At all. Period. In both our scenarios, the valve is in the process of dumping air. It's state beforehand is constant, and irrelevant.
A longer burst has to continuously do everything I said an air powered strafer needs.
So your 'argument' isn't even about the BBMG, it is about the air supply. If you are testing the gun's ROF, then you need an air supply that can keep up, unlike the one in your scenario. If you are testing the ROF possible from your air source, then you need to adapt your test to your shooting style.

Posted: Tue Apr 03, 2007 7:20 pm
by benstern
"unless it's electrically fed and fired"

Am I correct in assuming you are talking about the centrifugal bbmg?

I also stand by my 3 second rule.
It takes into account bbmg start up and low bbs/air pressure and full rate of fire.

In addition it is standardized. It can easily be used between different guns to determine standard performance.

Posted: Tue Apr 03, 2007 7:29 pm
by noname
BC Pneumatics wrote: In the conditions of my firing, there was not significant latency in air supply to cause a drop in firing rate. Sure, the first 1/2-1 second is bumpy, but anything after that is constant.
A short burst will have a better ROF because the BBs are loaded and ready
Actually, in the design of a typical BBMG from these forums, the BB's aren't 'ready' until they are in motion, so I guess this would be a point in the opposite direction you are arguing for. Thank you for bringing it to my attention.
There may be slight confusion in this topic because you are talking about a cloud strafer. Richardbridges and I are both talking about a vortex, because that's what he was planning on making. And with a vortex, the BBs are "ready" when their in the gun. As soon as they start moving, they're out the barrel. I was assuming you were also talking about a cloud, until you said the first 1/2-1 second is bumpy. Have you ever made a vortex strafer? If you did, you'd know what I'm talking about.

Posted: Tue Apr 03, 2007 7:31 pm
by BC Pneumatics
Am I correct in assuming you are talking about the centrifugal bbmg?
I think an airsoft gun would be a safer assumption
It takes into account bbmg start up and low bbs/air pressure and full rate of fire.
Erm, it makes the non constant start up factors play a larger role, making it overall less suited for a standardized reading that would be an accurate gauge between two guns. In your test, people are testing their air sources, not their guns. The truth is, most people don't have the resources to test their guns full, consistent, performance.

Posted: Tue Apr 03, 2007 7:35 pm
by BC Pneumatics
I have made a strafer, and what I said is still true. In a strafer, they are in motion in the vortex block, just as they are in a 'cloud' inside a cloud design.

I think you misinterpret 'bumpy' for 'erratic', by 'bumpy' I mean if you graph ROF over Time, it is not perfectly linear, not necessarily that it looks like the Sierra Nevada's.

Posted: Tue Apr 03, 2007 7:38 pm
by noname
Might just be my design then. Good thing to know I improved something, and now others are too!
I did misinterpret "bumpy," but thought it was more like a few at a time for the first second or so.