Time to resurrect this thread--
I'm on my third chrono--
First, my twenty-year-old PACT Mark II finally went bonkers--just wouldn't read, even after cleaning sensors, etc., and I've sent it in for repair. Because I wanted to keep recording data for my "short barrel" reloading project, I looked around and bought a Chrony Beta Master--i.e., with the remote head at the bench. I've used the Beta about six times--generally, it seems to work fine--except it does NOT like flat light (overcast), and the sweetspot for getting consistent readings was quite small (compared to the PACT).
I consider the PACT to have about a 5% failure rate for reading shots, and the Chrony seems noticably "touchier"--it was even impacted, I think, by gunsmoke on a still day, and I had to slow down shooting and carefully shoot in the sweet spot.
Meanwhile, last winter I had scoped out the CEDM2--since I am recording large quantities of data in my computer, its USB port and related software were really attractive to me. But as everyone knows, they've been out of stock here in the US for months. Then, last Thursday, in my weekly LGS visit--they were in stock! I promptly bought one, and finally got to try it yesterday.
The CEDM2 puts the the PACT and Chrony to shame for performance. On a spotty-cloudy, bright day, temp 65F, I shot about 350 rounds through it. I had no errors; all shots were recorded. The sweet spot is huge. There were 31 10-shot strings recorded--no problems there; it can hold up to 1000 shots in its standard form.
I am still learning command sequences, so unit operation was a bit of an issue--I haven't tried editing strings yet, and apparently a saved string cannot be deleted, only manually "omitted" once the string has been saved. One nice little feature is that fact the turning off the unit will automatically save the string in memory--and one does not lose the data.
So I got home, hooked up the USB port to my computer--and had a trouble-free download of all data. That data set was then saved to a tab-delimited file. I printed the file (on a standard printer) and found that in the course of data collection, it had read two shots as "flyers"--which the software notes with an "f" by that particular shot--but recorded the velocity anyway!
I printed the CED output file--and they provide a standard output that obviously will fit to standard calculator tape, or--if output to a standard printer--aggregates the strings into four column widths and puts about about 11 string reports on a page (with ten-shot strings reported). Pulling the tab-delimited CED output file into a spreadsheet (Xcel) file is a no-brainer--and the data comes in with a reasonable row format for the records, complete with headers.
One neat little trick was to provide a compartment for a spare battery. So far, the only negatives I've noted are a "cheaper" construction than the US-made brands--but still apparently satisfactory, and well done. I'm not worried about shooting it--I don't seem to have that problem with Chrono use--but for sure the damage will be significant. However, the easy disassembly and parts design suggest minimal damage possibilty, and easy replacement.
One potential problem might be the loose fit to the sensors on the mounting rod--they simply slip on the ends, and they are "loose." If they tend to slip off during setup or takedown, the plastic brackets and sunshades could get broken, I think, and I wonder just how fragile the sensors are. Preventing these potential problems, or at least limiting it to user mistakes, would probably only take a wrap or two of electrician's tape on the rod to tighten up the sockets.
However, it was the field performance where the unit really performs. The deeply-inset and wider sensors are probably the reason for that performance. I may try it again this afternoon (it's flat, with complete cloud cover today) to see how it does in this kind of light.
Overall, the CEDM2 is highly recommended if you want to work on your chrono output away from the bench.
Jim H.