Based on my experience using fixed head doppler radars that LabRadar looks to be too far away from the gun to give an accurate reading for muzzle velocity. One of the shots also gives a 3ft/sec difference between the two which would have been enough for us to have rejected that shot in our trials. Our radars were required to agree to within around 2ft/sec or less with muzzle velocities of 2500ft/sec.
Both the LabRadar and the FX are okay for general use chronographs but are subject to errors just like any other chronograph costing a fraction of the price and they probably need to be positioned more carefully than your average chronograph for an accurate reading.
The whole point of all the comments I have made on fixed head doppler radar systems such as the LabRadar etc. is that if you want an accurate reading they are anything but simple to use. In our trials using muzzle velocity radars skilled experienced instrumentation engineers would spend hours trying to get two units to actually agree to within the required limits. With just one unit you will get a reading most of the time but you will not know if it is accurate or not. Positioning and weather conditions are critical.
So simple to use, but prone to innacuracy... I guess it depends on what you need.
I'll stick to my old targettronics PM-1 If I can't shoot thru the 4" hole, I have bigger problems...
Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.
If I might comment on this, as you state your skilled tech's will be trying to set them to a pre determined limit
When Joe public, like me, shoots through his chrono all he want's/gets is a number, we don't know if that's accurate or what that degree of accuracy is either
Positioning & weather conditions are also fairly critical to set them up.
It's the difference between laboratory conditions & testing in the back garden.
I don't think 5 fps either way is a big deal for the hobbyist (particularly full-bore). If you are chronographing professionally - that may well be a different story - i'm sure the costs are way different too. I have a Chrony - I constantly get errors due to lighting conditions such fluorescent lighting (which I have no control over) or for some other random reason I can't quite figure out. I live in fear of accidentally shooting the thing If chronographing at a public range - there may well be problems putting a standard chronograph in the line of fire. Having your chronograph behind the line of fire is an advantage in these situations. 6 of one, half dozen of another - choose your limitations.
My take on accuracy is that if you can get to around 1% error rate - or 99% accurate, then your doing well, and arguably will not know when your results are either 99.5% correct or 100.5% correct - this is around 8fps in a UK .177 legal gun (4 under, 4 over). So if 2 or even 3 cronos are within 2/3/4fps of each other then to me they are all acceptable and all in the ball park for accuracy and the pellet weights or batch will be causing more difference than this.
I see this latest crono as an item which does not replace or add significant advantages over other cronos already on the market, it's just another alternative, and will be better for some people and worse for others depending what they have used in the past. I use a Combro attached to a Bluecron lead to a phone and it does everything this one does and more - as my one gives graphs. But then I can't do a shot string 30m down range - but how often do you do that, and other than a passing interest would you care?, but my set up cost half of what this one does and I've had it 5 years+, so why the fan fare for this?
None of this is slating the product, it could have been better, and it could have been cheaper, but as it is it's a welcome alternative to an already large market of air gun suitable cronos.
James
Making a mockery of growing old gracefully since I retired
There have been days when we were using muzzle velocity radars when atmospheric conditions wiped out the signal by swamping the radar with false returns. What was more worrying was on some occasions the radar would only get three or four data points but would still give a muzzle velocity value based on insufficient data. On the radars we were using we were able to see the amount of data collected, you cannot normally do that on the smaller simple sets available to the public. On one occasion it got so bad that I arranged for the range to buy a chronograph from Welsh Willy to check the figures we were getting.
On the question of accuracy I have often seen errors of +/- 2.5% with occasional errors of +/-5%. Ok if you have some idea what the muzzle velocity should be, not so good if you are checking a modified rifle for legality.
Please do not think I have something specific against the FX radar, I am mearly advising caution and care in their use. The LabRadar is the same with numerous reports from the US of people having problems with them and a large number of videos showing entirely inappropriate positioning by both amateur and professional users.
Anyone managed to use one of these with an underlever rifle - like a HW97??
All the images I've seen show them attached to the underside of the barrel, would it not work upside down, on top?
How good are these compared to a skan chrono? Or even against the combro?