This may have already been discovered by others but I found that a simple mod will make the cheaper sporter version work with a can (only tested on a Harvester 300 so far). Just take the rubber seat off of the bayonet so that the plastic is directly contacting the can. Move the rubber seat 180 degrees to the top of the can underneath the strap and tighten as usual. This brings the sensor close enough to the bore and keeps it axially aligned and tight so the sensor picks up readings without a problem.