Yeah, I even saw a Magnetospeed change POI on a .22 Hornet with a medium-weight barrel, by about an inch. That may not seem like much, but that's the LEAST effect I've seen. A friend's Ruger American Rifle in 6.5 Creedmoor went from a sub-inch rifle sighted-in two inches high at 100 yards to a 2-3" rifle sighted-in six inches high. Or somewhere around six inches high, it was hard to tell.
They're great for measuring velocity, though.
