Take the baby luger mainspring out, and with the unit unloaded and grips off, pull the toggle all the way back until the rear toggle stop touches the frame... Measure the distance between the end of the spring guide and the bottom of the frame spring stop web, at the top of the spring area..... Now, take your main spring that you are going to modify, and using a drill bit the fits in the inside of the spring, drill a hole in a piece of aluminum or plastic and using the hole, drill and drill press as a tool fixture, completely compress the spring to solid!! Measure, and grind some off, repeat until the compressed spring will fit in the area left on the spring guide at full recoil...
.. install and test! ...best to all, til...lat'r....GT
