I have used my MagnetoSpeed for 250 Savage up to 300 WSM and a few in between on the barrel as design intent. Have had no experience that would make me want to have the transducer independently mounted. YES, it effects point of impact, but the best groups with the bayonet attached are the best without. When load development is done, I take a couple shots to zero. Usually 1-2 inches high. I don't find this to be so inconvenient to need a isolated mounting system. Typed this on more than one occasion, and I definitely seem to be a minority on this, but it works for me.
This has been my experience as well. Even out to 1000 yards. With sporter weight barrels.
