I used to be a stickler for chronographing during load development, and used an optical. Then realized, when I gwt one shooting tight, it tended to also have a low ES. I never cared how fast it went, as long as it was consistent.
As far as the Magnetospeed, they give dang accurate numbers, but I don't want anything touching my barrel, especially during load development. "They" say all it does is shift POI, but I don't buy it. Its got to change harmonics. If that was the chronograph I had, I would develop a load without it, find the winner, and chrono after the fact.
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