I've added an adapter to my store for your DR650, front cam only. Try a search for "Blackvue DR650 cam adapter" to find it. Take a look at the picture in this comment. The left is the adapter for the DR500 and the right is for the DR650. From your measurements, the lens barrel of the DR650 seems to extend 1.13mm more from the side of the dashcam body. Therefore, I moved surface S1 (left design) 1.13mm up, resulting in surface S2 (right design). This should allow the end of the lens barrel to be flush (once again) with the end of the adapter (top of the picture), and the underside of the filter to not make contact with the end of the lens barrel. The surfaces S1/S2 are for the adhesive backed magnetic metal ring that comes with the MagFilter. Since I do not have a DR650 to test, you will be buying at your own risk. However, I charge no markup (I get nothing). Please let me know of your results!