When friends are real friends they are not afraid of telling you you're wrong ;-)
Well, as soon as I arrived at the Sherwood Forest GP, I noted that I was clearly going to be disabused of my idea by a good friend.
;-)
After a somewhat disastrous first day, the local Competition Electronics Pro Chrono told me that something was different. From shooting in the 770's, my MV had dropped to the 730's.
Second day I changed range cards and connected much better.
In a discussion with a well respected UK airgunner and ballistician (he was a professional in the subject), I had to look back at my notes and realized that the first Garmin I had tested had been the Trainer (and that is going back 8 years). Similarly, for the LabRadar, my experiences dated from 11 years before!
Geeze, where did Time Go? ROFL!
To cut to the chase: between my friends Greg Shirhall, that had expressed from the beginning his total disagreement with my statement about small radar Chronos; and John Cerne, that is a veteran experimentalist, I had my work cut out, LOL!
So, after the GP competition was done, we set a Chrono testing range:
The rifle would be placed at equal distance from BOTH chronos, and the chronos would register the same string of shots.
At the end of the test (necessarily short because everyone was exhausted after two grueling days of competition), the results were pretty even:
The Garmin read an average of 766.3 fps:
I was a bit surprised that there aren't more numerical data than Max, min and Ave, but then both devices transmit immediately via BlueTooth the data to the owner's phones, so exporting that data to an Excel file should be no problem.
Arriving at home, I checked on my Caldwell and the results over a 20 shot string were (back to normal): 775.2 ± 2 fps.
Does the difference between 763-766 to 775 bother me?
Nope! there is a 1000' of elevation above sea level difference between the two venues, so that is perfectly in line with I would have expected from the CCA D-54.
Now, the 10 fps "lost" do not "jive" with the 30 fps that the Competition Electronics would seem to have indicated, but in general, I do not argue with reality. And I would think that the main source of error when using a "natural light" triggered chrono is actually the inclination of the light vis a vis the reading length. This is worthy of note as shooting down into the ground is a SAFE policy, but it may not be the best as far as chronoing goes.
That deserves more experimentation.
One thing that was VERY evident is that the newer Athlon Rangecraft chrono reads MUCH faster than the Garmin Xero. Again, difference and advances in firmware over the last few years. Not something to be too worried about if you are a springer shooter, but if you have a semi-auto, it could be an important factor to consider when making the purchase.
So, there you have it, I now can say that the MODERN small radar Chronos are as accurate as the old light screen based ones.
Progress!
;-)
Keep well and shoot straight!
HM