The half-cock feature (actually a ledge not a notch) was added to the Colt Pocket Model in-or-around 1922, at serial number 422000 (32) and 66000 (380). It's sole purpose was to prevent a cocked hammer from following down onto a loaded chamber, if the sear - for whatever reason failed to hold it.
IT IS NOT INTENDED TO BE A CARRY POSITION WHEN THE CHAMBER IS LOADED.
To check it's function:
1. Remove the magazine. If your pistol has a magazine disconnect safety, unload the magazine. Pull back the slide and inspect the chamber to insure it is unloaded. Put the loose cartridges someplace where they cannot unintentionally be loaded into the pistol.
2. With the slide in battery, and the unloaded magazine inserted, notice that the safety lock (manual safety) cannot be engaged, and the grip safety is in the "OFF" position.
3. Pull the slide backwards about 3/16" to 1/4". You should hear a "click." and you can now engage the safety lock, and the grip safety has popped out to the "ON" position. Now lower the slide on an empty chamber. If you wish you can reload the magazine and insert it. BUT DO NOT CYCLE THE SLIDE AND LOAD THE CHAMBER UNLESS THAT IS YOUR INTENTION. IF YOU DO SO BE SURE THE SAFETY LOCK IS PLACED "ON".
The pistol should be carried with the chamber and magazine loaded, and the safety lock engaged.
or:
With the chamber empty, the magazine loaded, and the safety lock either "ON" or "OFF", depending on the user's preference.
