OS 40 LA main port

Modification has accomplished on OS 40 LA forming the Schnierle main port successfully. The procedures were done on both cylinder sleeve wall and forming gas way inside the case. Keen concentration and special tools such as Carbide cutter were required to carry it out.
Because this modification is experienced on OS 25 LA motor last year, the task on 40 LA was not so difficult one but not so easy.
Later investigation about 40 LA models proved that the end stage production model has main Schnierle port, that has one piece rear cover plate with the needle valve body, not an independent metallic holding stay.
As I have formed the main port with oblique angled gas way to grow plug direction, manufacturer's design of it is horizontal parallel to the piston top surface.
I'm looking forward to compare my modification with originally 3 ported 40 LA model.