Velocity Consistency at Playing Conditions Rate of Fire

[nak81783]

21-Oct-2023 Update: See post #10 for TiPX data.

02-Nov-2023 Update: See post #23 for weights on nylon riot balls.

[nak81783]

Constructive criticism welcome. Anything else I should test?

[drewkroeker]

I don't really have anything to add. I'll just say that such consistent velocities make me happy I picked up an emek. And then another. And another. And then an etha 3. Is there any way to tell how accurate your chronograph is vs something like a handheld X-radar? I'm assuming yours is more accurate just because it has larger components but that is not the scientific way to tell lmao 😄

[nak81783]

Unfortunately, I don’t have a way to determine precision of my chronograph. Furthermore, with such a large spread when I use actual paint, which is what I use at the field, I can’t comment on correlation either. I’d want to test the field chrono with the nylon balls to determine correlation, but I’m not sure how to accomplish that.

[MrBarraclough]

nak81783 I wonder if a secondary method of measuring could be high speed video. A camera mounted at a fixed point perpendicular to the flight path could record each shot. The time to pass between the two wire frames of the chronograph (a known distance) would give you speed. You'd need good lighting and a constrasting background. The two confounding factors would be the relative angles between the camera and each wire frame and then the framerate. Positioning the camera precisely perpendicular to the midpoint between the frames would mitigate the former a little, as would increasing the distance to the camera. As to the latter, a high framerate would reduce the magnitude of the error, and at least the magnitude would be a known value.

Someone better at optics than me might be able to work out the magnitude of the error introduced by the angles, and perhaps compensate for it or at least give you an idea of the error brackets involved. Since the angle error could potentially stack with the framerate error (or cancel), it might be that the result would not be precise or reliable enough to be useful. Or maybe it would be.

[Fossilhead]

👏
great job!

[Trbo323]

So what are you testing for though?

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[nak81783]

I was just curious what consistency each of my markers had at a playing conditions rate of fire when taking inconsistent paint size out of the equation.

[Trbo323]

I was just curious what consistency each of my markers had at a playing conditions rate of fire when taking inconsistent paint size out of the equation.

O ok, this whole thing makes more sense now

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[MrBarraclough]

Great job.

I'd love to see a large sampling of your nylon projectiles weighed individually to determine what the standard deviation is for their weight distribution. I infer that you were using the nylon balls interchangably, not recovering them immediately and using the same 10 or 20 for each group.

It's interesting that the broken balls show a significant cavity in each. I'm guessing that nylon cools and hardens pretty rapidly and that molding spherical shapes precludes degassing before they harden. Perhaps the manufacturer degasses the molten nylon before molding, but the molding process probably reintroduces some trapped air. I wonder if the manufacturing process tends to keep the bubbles/cavities towards the center, or if some balls come out of the mold with craters and those just get rejected at the factory.

[nak81783]

In slow fire testing, I've recovered the same nylon ball each time, with very similar results/spreads. For this higher ROF testing, you are correct, I loaded the 100 that I had in the hopper and let 'em rip. I wanted to keep the hopper full to avoid skipped or delayed shots.

[glaman5266]

Neat.

Those paint velocity numbers are insane. Out of curiosity, what paint was this and how fresh was it?

[nak81783]

GI Custom. I cannot comment on how fresh it was, other than the field seems to sell quite a bit of paint, so I'd think they have regular shipments.

[nak81783]

Here's some info on a Tippmann TiPX using same method as previously described.

HPA was used unless otherwise specified.

CO2 shoots hot, so I chrono'ed it down to 225-230fps on HPA before shooting with CO2.

Not sure what happened on HPA Stock Barrel Fast Fire. 2 shots didn't register for some reason.

For the groups shot with CO2, I did shoot either slow or fast per the description. However, I also wanted to see how many shots I got on a 12 gram, so the magazine re-load skews the shots/second.

[Trbo323]

Wow that standard deviation on the co2 was something to consider. Pretty big difference

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[Seajay]

I think it would be interesting to see if the SD changes are impactful with all the markers were chrono at 280fps.

[nak81783]

I'll keep that in mind for the next lazy rainy day. I'm down to 5 markers though - Etha 3, Etha 3M, Empire Sniper, TiPX, and EMF100. I recently changed up my collection to focus on markers for different play styles - electro, mech-semi, pump, mag-fed, and pistol.

[minimag03]

Curious if the OP would be willing to test and old theory of mine about cockers vs mags, Everyone back in the day used to swear cockers had better 'range'.

My theory is that some of the cockers did in fact have longer range (during rapid fire) because their regulator setup.

This was caused by setting their HPR above the cocker's 'sweetspot'. As the gun is fired quickly, the regular's pressure output could drop because it cannot keep up with the rate of fire (remember the quality of regulars back then lol). The lower output pressure from the regulator would result in higher FPS.

You'd need a cocker and example of old school regulars. But I'm confident this theory could be proven true under certain circumstances.

[Brokeass_baller]

Warpig did an open bolt vs closed bolt shootout, and the results were nearly identical.

Add to the fact that Uniregs were basically Automag regulators, and were the de Facto reg for a long time, leaves me to believe that it's mostly just placebo.

[minimag03]

I'm not saying there is truly a difference in 'range' when both makers are shooting the same FPS.  Nor am I saying it was a common occurrence. But i'm certain it's possible under the right circumstances. Especially on older cockers that were heavily modified for LP, where they're constantly hungry for a large volume of LP air. That's not something older regulators were known for doing well, the Unireg included.

I use to have a Bob Long HPR, the kind that was black with silver top and bottom, that had horrible recharge rate. Could never get the thing to work right. It would have been a good candidate for such an experiment lol

[Chappy]

If you set up a cocker above the sweet spot spot it will spike fps when the tank pressure drops at the end. So if you could outshoot the reg causing the pressure to drop then absolutely this could happen. I Think the question is whether you can consistently get more then a few fps to make a noticeable difference.

[nak81783]

I no longer have an Automag or Autococker. See comment further up in thread.

What I will say is, in addition to the other comments, I shot
Automags and Autocockers for over 20 years, tinkering with all
kinds of settings. Both great guns. Both shoot the same distance when operating properly.

Yes, the fps increase you describe could happen and result in slightly longer range. Noticeable? No.

Remember, RT/X-Valves spike during rapid fire. This is why they have a different chrono procedure if you don’t want to exceed a set limit. So, in a different way, the same claim could be made for RT/X-Valved Automags.

Both come down to quirks/imperfections in their regulators.

[Deerslayer]

I was just curious what consistency each of my markers had at a playing conditions rate of fire when taking inconsistent paint size out of the equation.

If we assume the nylon balls were uniform (not necessarily a good assumption) then what you were testing was the gun's consistency to process the same amount of air from shot to shot. You could weigh and measure a number of balls to check this.

What was your bps rate of fire? IIRC, my PACT chrono's manual said to wait 1.5 seconds between shots (I'd have to look it up again to verify). I would think this too would affect your velocity consistency. In the end, I think doing this test with paintballs is probably a better way to get a handle on your gun's performace under actual game conditions.

[nak81783]

The S/sec in each screenshot gives the rate of fire.

There are two groups in the first post with paintballs.

[Deerslayer]

Thanks. I did not understand the S/sec. I saw the paintball/Etha runs and noted that the SD was quite high. I'd expect that to hold with non-uniform pb's.