Recent content by Gwhite

My circuit design skills are out of date, but to save power, I wouldn't expect them to try to do the actual time interval measurement in a "processor." A dedicated CMOS interval counter could be clocked at a high rate without having to run everything else that fast. The HT-X3006 sensors are...

While going over the data in the previous plot, I noticed that the velocities tended to only take on certain values. That suggested that the chronograph had limited resolution, and that the results are "quantized." I did the original measurements in FPS, and I took that data, and sorted it by...

I've been tied up with other stuff, but I went through my notes and found a couple of promising pistols that I rebuilt several months ago. One of them is a Hammerli 480K that was upgraded to the use the Hammerli AP40 regulator system and cylinders. I typically only tested the velocity for 10...

I really like the Combros, and actually have 5. One I bought direct from the source many years ago, one was new old stock from a Canadian vendor, and three came off of eBay in the US. Two of those have been shot, and someday if I get bored, I will see if I can combine them to get another...

I'll have to check the height of the sights relative to the bore for the various pistols. 15 mm may be too much to use the sights properly on some of them. The 3D mounts are reasonably rigid, and the HT-X3006's are quite light. The cable hanging off the Nate Chrony might be an issue., but...

All my HT-X3006 adapters are already out there: https://www.thingiverse.com/thing:6977381 I think I can just create a single dovetail adapter that fits the Nate, which would allow reusing the mounts I designed for the HT-X3006. I want to be able to use the sights on the pistol when...

I'm aware of the Nate Chrony, but haven't really looked into them in any detail. For tuning purposes, 1% accuracy of absolute velocity is fine, but I need REPEATABILITY better than that, which is a number nobody else specifies, but the Nate appears to. The Combros were apparently live fire...

I'm not sure that is much of an issue with the air pistols we shoot. The mounts I have 3D printed for the Combro put the muzzle about 2 cm back from the first sensor, and the mounts for the HT-X3006 are similar. Because the turbulence of the air exiting the barrel can affect the accuracy, most...

I have a 3D printed sight with a tube on top, but if the LabRadar beam is off center from the face, that doesn't help much. When I get time, I will drag mine back to the 50 foot indoor range and try again with an SD card so I can monitor the SNR. I really need to fix more pistols, not become...

One note on the LabRadar beam. The specs say the beam is 7.6 degrees by 18.5 degrees, but they don't say which is vertical & which is horizontal. I asked the factory, and the tech support person had to double check. I had assumed the 18.5 degrees would be horizontal to help with acquisition...

Thanks for the very detailed info! It would be nice to know the velocity, but the range for the Benelli Kites is 135-145 m/sec, so it's not super critical. What's important is the repeatability. Given that I've measured +/- 1 FPS on some air pistols with a Combro, they have to be pretty...

Thanks for that info! Given my results with the LabRadar, I'm very suspicious of radar chronometers. At least it sounds like the problem with short ranges & reflections isn't an issue with the Xero. It would be interesting to see side by side results of a Xero and an FX (or an Athlon)...

I'm using moderately dry air from a SCUBA tank. When I have a properly tuned up pistol working really well, I get +/- 1 fps readings from a Combro. I need to go through my notes and see which pistols could do that, and use them for my testing. I've repaired about 20 pistols in the last year...

Thanks for the feed back! I didn't bother with an SD card. I'm new to the LabRadar, and didn't realize it stored SNR data on the card. I plotted the results: The first shot looked very promising, and then it rapidly went to hell. I started out at the low power setting, and had very...

I am the team "armorer" for a US college pistol team, and I'm learning how to repair competition 10 meter air pistols. An important part of the process is measuring & adjusting velocities. In the past, I have used Combros, which are spec'd to be 1% accuracy. I have two at home, and we have...