Thursday, May 2, 2013

[Rant] Range test witchcraft.

Jump if you want to read this. Warning: Science content, frustration, and criticism of the NIC mainstream inside.


I have long hated range testing. I am not going to lie, the rudimentary level of accuracy in measurement and in popular understanding of nerf ballistic performance is obviously holding us back from further development.


To start: What's a range test?

It is a means for vaguely measuring ballistic performance.

You get a gun, and some darts, and you go out to a suitable location with flat terrain. You shoot darts from a pseudo-standard height and usually a pseudo-flat elevation, and then you measure how far away they landed.

There are some people that do it with a fair bit of honesty, reliability and certainty and provide a tangible idea of ballistics to the community using range test videos - and of course I am speaking of fellow HVZer Randomshadow09, who does an excellent job of it for many a product in the nerf industry. Don't get me wrong, this is not what I am about to bash into the ground.

Rather, it is use of range tests by NICers and serious modders who somehow continue to defend their validity and worth to modders even as they are fully aware of and perhaps even own chronographs!

My guess is that range testing and the practice of quantifying a gun in terms of ranges originated in the early NIC, when the hobby was more just some people doing some rudimentary tweaks to toys, than an actual hobby like it is now. In short, range tests were our field expedient replacement for chronographs that simply weren't justified at the time - too costly, or not even known to the nerfers involved.

And for that purpose, ranges worked. You threw some rubber bands on your LnL, let's see how far that thing can chuck a micro out of the marker body you hot glued on the end.

Nowadays... not so much. I don't think I need to explain any farther.

Yet a distressing consequence of the early use of ranges seems to be that "range" is now an ingrained concept in the NIC and is the "natural" way to address performance. When someone posts a mod, the question is not what velocity it shoots with some given dart - it's always, ALWAYS "Ranges?" over and over again. If you hand them a velocity, they aren't satisfied until you give them an equivalent conversion to NIC Standard Range Test* numbers.

Now, that wouldn't bother me all that much, because ranges have been used in the past and change on this front is not going to be fast...

Except it's worse than that.

I recently came upon this discussion on a certain nerf forum in which user azrael brings up a good point, says some very wise words and everyone else absolutely fails to see the light:

azrael: TBH, I'm a bit over ranges. I don't really trust people's measurements anymore. I feel like the only accurate and universal measure of performance is the use a chronometer.

Anonymous User 1: Chrony is decent, but it's not an accurate and/or universal measure either. You can still hit 100ft with 180fps, or 250fps... There's more to it than just how fast the dart is going.

azrael: It's a very real and definite way to determine how much a modification has improved the efficiency of a blaster. I said nothing of hitting 100ft, unless I'm mistaken?
It's accurate if you do it correct. Not everyone does it correctly.
 

Anonymous User 2: The problem with ranges is that we want the results to be statistically accurate, with controlled methods used, but at the same time, we want them to be "real". These goals are incompatible, as conditions on the field are usually quite variable and do not match ideal stats. For example, we like to say that our ranges are measured flat. But, and I forgot whose test this was ([usernames redacted]), we rarely actually level our blasters when shooting in wars. There's almost always some slight angle used, consciously or not. So, if you do level it in a test, you'll get more accurate and less accurate results - more accurate because it's exactly PTG, less accurate because we don't shoot that way.

Thus, I think that the most useful range testing method is to grab a ballpark/average range and letting the conditions fall as they may. It could be colder and warm up, there might be wind that shits in direction and speed, some darts/foam may be better than others, but oh well. After many shots in differing conditions, you should see some kind of ballpark that is reliable. When someone says x gun shoots y feet, I don't think of y as its max range, I interpret y as its average range, the range you are more likely to see in battle and hit the most often. Its max range is understood to be something you will only hit in ideal or enhanced conditions, and thus is not useful enough to be cited as its primary range stat.

Chrony, as mentioned by
Anonymous User 1, is only good for speed and not range.


Wow.

I don't even know where to start with this.

The definitions of "accurate" and "universal" that people aside from azrael seem to have in this thread are uniformly 180 degrees from the truth.

You can still hit 100ft with 180fps, or 250fps... There's more to it than just how fast the dart is going.

That is precisely the problem with range testing. There is a lot more to it than shooting the same velocity with the same dart and always getting the same numbers out of a range test. Range tests do not work that way - they have far too many extraneous variables to be ANYWHERE NEAR accurate or universal as a performance measure. They are subjective, biased and easy to cheat, as well - just as azrael stated earlier in the thread these quotes were pulled from. 

If I was on this forum I could argue this point to the end of time, however, and still get nowhere.

That's because ranges are being treated as a meaningful performance statistic in themselves.

First of all, NIC range tests (which measure MAXIMUM range) mean absolutely nothing for EFFECTIVE range. If you want to talk about effective range, you have to know the farthest your projectiles will go while still being accurate and still retaining enough velocity to tag someone out. Range TESTS do NOT do that. Range tests, in general, do not quantify any combat-relevant aspect of the performance of a system in anything aside from general terms. Range tests are a ghetto chrono, nothing more. There, I said it. Simple.

Second - and this is where the "witchcraft" part comes in - people STILL seem to hang on to the idea that the maximum range of a known projectile under standardized conditions can be affected by some unspecified voodoo factors OTHER THAN velocity.

THIS IS FALSE.

As long as you aren't shooting yawing unstable projectiles, 200fps is 200fps. If you have 3 idealized guns each shooting the same dart at 200fps and fixed to a bench rest, THEY WILL ALL ACHIEVE THE SAME RANGE TEST NUMBERS.

There is nothing you can do TO THE GUN, say using a different barrel material, that will arbitrarily make a 200fps dart launched at an angle of zero degrees to the horizontal under the same conditions as all those other identical darts do ANYTHING but travel the same distance. Perhaps you could make it more accurate by stiffening the barrel or crowning the muzzle - but the simple physics still are that two identical mass projectiles with identical coefficients of drag launched at the same angle and velocity will travel the same distance before returning to earth.

So anytime you DO see something chrono the same as another gun with the same dart and then shoot a different range, EXTRANEOUS VARIABLES WERE INVOLVED. Perhaps one gun recoiled slightly and thus didn't shoot at zero elevation. Perhaps the barrel resonated and flexed. Perhaps muzzle blast blew that dart off into having an upward velocity component. Perhaps the physical design caused the shooter to shoot with elevation. Perhaps it's all experimental bias, or random variation that isn't (statistically) significant.

SO IF YOUR RANGE TESTS ARE MEASURING THINGS YOUR CHRONOS CANNOT, THEY ARE MEASURING ERRORS.

Not performance. Not safety. Not "how well you modded it" or "how hard it shoots".

That's what it really comes down to here, doesn't it? People are not necessarily missing the fact that range testing is inherently flawed and fuzzy so much as having the wrong idea of WHAT TO MEASURE. Those factors other than velocity? They are UNWANTED and EXTRANEOUS. And, most of them are unpredictable (i.e. muzzle blast, barrel vibration) or meaningless (i.e. gun design that entices shooters to arc their shots) in combat. They are CERTAINLY meaningless to any kind of tuning or modding of a gun. You don't WANT to include them.

If you want to know the "performance" of a gun, the simplest and most direct way to communicate and quantify that is to chronograph with a known projectile. From that you have exact data to accomplish any of the goals of range testing in the first place. You can compute muzzle energy, quantify efficiency. For analyzing the effects of mods and tuning - barrel lengths, dart/barrel matching, springs... - velocity is FAR more direct and accurate than range tests.

Chronographs are exceedingly accurate, reliable and convenient, near impossible to cheat, and cut out 90% of the extraneous factors that threaten to turn your range numbers into worthless garbage rather than data. If you want to know ballistics, the velocity and the projectile just TOLD you everything you EVER needed to know that isn't related to accuracy - an entirely different subject.

3 comments:

  1. Toruk, I want to hug you and have your babies. I have been waiting for someone to say this for a long, long time! :D

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  2. I totally agree.

    My BBB can hit well over 100 feet flat. However, I couldn't hit my shed consistently at ranges any greater than maybe 70 feet, let alone another player who is moving. I think that measuring ranges is a very simple means of roughly measuring how effective your mods are. Not a measure of how effective your blaster is. A very important discrepancy.Somewhere down the line people have lost sight of this.

    I guess at the end of the day, not everyone can afford a Chrony but most can afford a tape measure. Unfortunately I think the 'range' debate will be around for a while.

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  3. Man, I can't agree with you enough. This whole range thing really annoys me, especially when people claim their "supa moded lonsot" hits 150 ft. Flat.

    Yeah, Maybe if you have a 787 taking off behind you.That conversation that you posted with azrael, ugh. People are just sometimes idiots, I felt bad for him.

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