so, much better today. This was my 1st target at 100 yrds with the ATCR and Spuhr mount. Top right 168 gr Fed match, center and bottom right 150 gr Wolf, bottom left 124gr Remington, top left PriviPart. 147. Last week ALL the targets were like the top left. Then I put the Burris QD mount back on (in the correct direction) with the original NF scope and the groups opened up again, but not as bad as last week. I think you are correct, the Burris mount has to go. I did move the scope forward to 1/2 inch past the charging handle. Any further forward and my cheek was rolling over the edge of the cheek piece.