I considered that, but with the shim removed, there is no clearance at the front of the cylinder, while the CHS is .078. So then it is a mystery, if the shim was not installed during the 1954 FTR, where did it come from? If it had an CAI import mark, that would explain things. How did armorers adjust the fore and aft position of the cylinder to assure the proper clearance on both ends?