It really does vary wildly. Large events are rarer than typical game days.
Generally speaking, everybody
should have their guns chronoed once in the morning before playing. Typically there will be a set time for everyone to chrono, followed by a safety briefing before the first game, then (regardless of what the site has said about it) late arrivals will get chronoed and hold everybody up before the game starts.
- How many stations are there at an event? Is there a rough number per attendee that would be ideal?
At a typical game day with 30 - 100 people, you'll be lucky to see two chronos. They're typically cheap Xcortechs, knock offs, clones, or feature equivalents of them.
I've never seen sites check their chronos against each other, so if they're using multiples, it's a lottery which one you'll get. I bring my own (cheap, generic) chrono, check myself before the site does it, and then compare my reading to theirs to self-calibrate against that specific site. Sadly, I take it a lot more seriously than most sites really do.
- Most appear to supply bbs to check with, typically 0.2g
Some do, some don't. CQB sites tend towards it, as they're more likely to have a weight limit, typically 0.25g, so feeding 0.2g isn't too far off. I've seen CQB sites keep M4 mags with 0.2g BBs to hand, as many players use M4 style guns that will take them. Otherwise it's a case of the site putting BBs into the mag (often having to eject some first because players don't listen worth a damn).
However, feeding 0.2g into guns tuned for 0.28g+ isn't particularly useful. You mention "Joule creep", so I take it you're aware that some (not all) airsoft guns, particularly full cylinder / long barrel guns like DMR and snipers, and gas guns, can impart significantly higher energy to heavier BBs as they linger in the barrel longer than a 0.2g would.
The sites where I play now all just ask us what weight of BB we have loaded, which is fraught with issues, as players can get it wrong, sometimes genuinely - a fair number of people use borrowed guns and just get handed mags - and sometimes maliciously.
- It would be good to be able to specify BB weight quickly? Joule creep etc (most fields are moving to this instead of 0.2 BB tests?)
The variety of BB weights in use is somewhat of an issue. People can and do show up with 0.2g, 0.23g, 0.25g, 0.28g, 0.3g, 0.32g, 0.36g, 0.4g, 0.44g, 0.45g, and others, more than a typical Xcortech knock-off can be pre-set to calculate for. Some sites will keep an fps / weight / Joules chart handy, some will re-program the chrono, some will shrug and guesstimate what the Joule figure might be.
- You take multiple (3?) shots & get an average reading, or is 1 enough?
Typically 3, and the highest matters. Although if you're fractionally over, some marshals will ask you to put more through and see if it was a freak. If you're slightly over, they might suggest running some mags through as springs can soften slightly as they warm up.
There are different energy limits for different types of gun. Typically these are:
Automatic guns, or anything that you want to use up close without a minimum engagement distance: 1.13J - 1.2J (depending on the site)
DMRs locked to semi and which have a minimum engagement distance and a restriction on rate of fire (notionally, it's rarely enforced): anywhere between 1.5J and 2.3J, with 1.88J being fairly typical.
Bolt action snipers, with a minimum engagement distance: 2.3J - 2.32J
Legally speaking, the limits on what define an airsoft gun are 2.5J for single shot guns, and 1.3J for anything auto-capable. So sites aim to come in comfortable below those.
There are regular issues with people shooting on the piss through the sensor, or gas guns throwing it off and needing to be shot from further back, or having to take a few shots to vent excess gas, or tri-shot shotguns producing wild readings. A lot of it is muddling through, and sites don't really want to be telling players that they can't use a gun, or play at all.
- If its below the velocity for that specific class then you pass
Yes, and typically sites will put a coloured cable tie somewhere on the gun to indicate that it's passed. This is itself open to abuse as cheaters can just bring a bag of ties, and guns tend to accumulate a rainbow of tags which are sometimes - but not always - snipped off.
To ameliorate that problem, I've seen sites put the tie on, but not clip off the excess until everyone is walking on to the first game. One of my local sites is now recording the figures against your name on the sign-in sheet, but that has another issue in that it doesn't indicate
which gun has been chronoed. I tend to bring three or more as spares or for variety, and sites are inconsistent on whether green gas pistols should be chronoed - even though there are some that shoot hot. CO2 pistols generally should be chronoed, but as side-arms tend not to get tagged, it's trivial to not bother.
Now, with all of the above said, my personal position is that pre-game chrono as described above is a complete waste of time for the purposes of catching malicious and dangerous players, because it's so trivial to game or avoid it. What it does is to let honest players know that they're hot, so they can do something about it before they play. But honest players aren't the big risk.
The only way to catch a hot gun in game is to catch it
in game, using site BBs of a known weight. Despite what sites may claim, this very rarely happens. I've only been chronoed in-game
once, and was just asked what weight of BB I was using. I'd like to see it happen a
lot more.
