I love 1911's and shoot them in competition. Springfield custom shop build and Les Baer in .45acp and recently a Guncrafter Industries in .40S&W. So I bought a L-10 Machine frame (2011 style) a few years back and had it in the safe. A year ago I grabbed a Caspian slide in .40S&W. After grabbing an Index 645 last year and a surface grinder recently, I got a little anxious. Got my dimensions for the frame and slide and determined where to cut. Due to the 2011 style frame being thicker at the back, I measured the rail and rear of the frame. Made a quick shim that measured .0834. Laid it on the SG and checked with a dial indicator. Before cutting anything, I looked over my measurements and realized i did not need to cut anything off of surface A. Being .00175 undersized is within recommendation of .003 or just over at .0035 if you add both sides together.