Just remember, if your rifle has double set triggers, it is not the same as all hammer guns. It is not the same thing as a exposed hammer, single trigger cartridge gun.
Guns with double set triggers have a device that blocks off the half cock notch so the sear will not enter it while the hammer is falling from the full cock position. It is called the "fly" and it is necessary to allow the hammer to fall directly from the full cock position to the fired position wihout getting hung up in the half cock notch. This is very different from a single trigger gun.
The only safe way to get a rifle with double set triggers to half cock is to either, raise the hammer from the fired position directly to half cock without your finger on the trigger, or to lower the hammer from full cock to a position that is less than half cock and then, without your finger on the trigger, pull the hammer back up to the half cock position.