Reply To: FX Radar

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bandg
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mmahoney

The results were really bugging me so I did a lot more testing today. First I ran a velocity distribution for the entire shot string. The gaps between the readings are not a good sign of accuracy. This is the same shot string measured by the FX and the Caldwell….The distribution of the Caldwell looks correct…The FX not so much.

Then I shot hundreds of pellets through both chronographs again with the FX moved to different positions. I've found that moving it forward or backward along the muzzle has little impact, but moving it closer or farther away from the muzzle makes a huge one.

Summary: My FX Radar likes the top of the chrony to be located 2.75 inches below the center of the muzzle opening. Being an inch in front, flush, or behind the barrel makes little difference. The unit happens to be 2.75 inches tall making estimating the distance easy. If too high or too low, the velocity reading seems to be reported too low. The problem of lots of duplicate velocities and gaps in the those velocities continues, however. My conclusion is that the Caldwell is more accurate.

Very nice work that will probably help many.  I would be perfectly happy with the FX given the two comparison strings above IF it did it repeatedly.  Seems it is too sensitive to position for this to be the case across multiple guns.  It might work well for a single gun once the "sweet spot" is identified but that seems to be a pretty big task.  Maybe they can improve it but it looks like it's not ready for prime time now.  Thanks for the effort to do this comparison.