I have one it works and proves to be accurate when checked against my buddy's Labradar.
That said I dislike having to load up extra rounds to get an idea of velocity when working up loads. On my pencil barrel Kimbers there is certainly a POI shift I experience. I can see the light magentospeed having minimal effect on a varmint barrel and such but it def drops the POI on my lightweight rifles.
I have the original Magnetospeed and the dial wheel control is broke and I am limping it along for a bit more....hoping it will make it till christmas when I ask for a Labradar for christmas. Labradar IMO is just as quick to setup. Also the Magnetospeed has a hard time staying put between shots on the pencil barrels. On my fatter barrel it does ok, but after a couple shots on my Kimbers I am stopping to redajust and retighten. It works and I certainly like it better than my beta chrony but there is enough about it that I don't like that my big Christmas present request is a Labradar.
