I had an identical problem with my Surgeon Scalpel. I was thinking, eccentric bore in the Suppressor. I tried different ammunition, same story. My suppressor was a Gemtech HVT-THD. After consulting with Gemtech and Surgeon in a conference call the "Brain Trust" suggested that it was eccentricity of the bore. The culprit....the QD mount. Long story short, Went to a Thread on mount problem gone, relatively. A 175gr Sierra HPBT with a 200yd zero with no can was 1.75" low with the can, no problem. Just my experience.