Thread: Half cock or safety

Originally Posted by No.3

OK, (big sigh).

Someone touched on this previously, the history of the 'half cock' in NZ springs from the Lee Enfield rifles where the back of the bolt has a little lump machined into the back of the bolt that guides a knob on the cocking piece. This is designed to ensure that the rifle will only fire with the bolt fully in battery, or fully closed. If the bolt isn't fully closed, the knob on the cocking piece slams into the little lump in the groove in the bolt and either throws the bolt over to the right locking it fully into battery, or to the left fully opening the bolt. Combined with this is a second notch under the cocking piece that was designed to catch the tip of the sear and lock the bolt in position in the action and also to prevent the firing pin from going far enough forwards to initiate the primer.

Some wise arsed Kiwi noted this setup, and cottoned onto the fact that it could be used to lock the bolt into position meaning the little fiddly lever of the safety catch could be dispensed with - but it's dodgy in use as not all cocking pieces and bolts were equipped with these features and also you could slip and stuff up the manual engagement of the 'half cock lock' and accidentally discharge the round.

This didn't really apply to most other rifle types, and Kiwi's have been trying to mimic the feature ever since to varying levels of success. Most rifles are not designed with such a system built into them, so some don't work at all for this purpose. Other types don't have 'out of battery' protection so you could theoretically discharge on a half locked bolt which is potentially a colossal clusterfluck looking for somewhere to happen. I'm not really in favour of the half cock unless it's a designed in firing pin blocking type with out of battery protection - and as noted most rifles don't have this.

Some rifles will actually drop the bolt and fire if you pull the trigger with the bolf half cocked