[Hugh]

I have run across three different width of slots in Luger grip screws. The widest ones were on new after market screws. I believe the early commercial Lugers had narrower slots than the later military ones. There were apparantly two different threads also. I have two sets of dies & taps for recutting grip screw threads, one is 4.5mm x .8, the other is 3/16in x 32tpi english threads. Most of the ones I have seen were the english threads, I have seen maybe two or three in the metric thread.