When setting up your trimmer for a particular case , make sure to chamfer and deburr before measuring the case you are using to set your length . Or you won't get consistant measurements . Trim , deburr, campher , measure , adjust trimmer as needed . I always put the fine (outer) collar in the middle of it's adjustment range before starting . Put a case in the trimmesr and move the Inner collar up tight against your trimmer , with the cutter tight against the case mouth . Then turn the outer collar away from the trimmer body , to make cases shorter , inwards to make them longer . I'm thinking your problem was not deburring before measuring your sample . Am I right or wrong ? I have been using the Lyman universal for god knows how long . If you spring for the carbide cutter , it will probably last a lifetime !