No4 Mk1* 1/2 cock

[skeet1]

Can someone tell me what the purpose of the 1/2 cock notch in the cocking piece of my No4 Mk1*. On my rifle when you pull the cocking piece to the 1/2 cock position it locks up the bolt and the rifle is in a safe condition. What I don't understand is why it was necessary when the rifle already has a good safety that is easier to use. There must be more to the story?

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[Peter Laidler]

Ah and good question......... It is called mechanical safety. The problem with a bolt action rifle is that in some instances you can fire the rifle with the bolt partially closed. But partially closed also means, by definition, that it's partially open and that ain't a good idea. So without going into all of the actual mechanics of it all, if you try to fire a No1 or a No4 with the bolt half closed, caused by being stupid or, say, dirt on the round TWO things can happen.

If the bolt is closed to PAST a certain point and you squeeze the trigger, the safety stud on the cocking piece will strike the safety stud to the rear of the long and........ I'll cut to the quick. The bolt will be closed mechanically. BUT in being closed, it will fire in the usual way BUT, because of the mechanical friction that has taken place, the spring loaded striker will have been robbed of a massive amout of its stored energy. Thius will result in a 'diminished force of blow' and while the bolt will close, the rifle will not fire/

If the bolt is closed UP TO a certain point and you squeeeeeze the trigger, the safety.......... I'll cut to the quick again....... The cockingpiece and striker, under the pressure of the stored energy within the striker spring will move the cocking piece and striker forward. But then, machanical safety takes place and the two studs on the bolt and cocking piece meet, one behind the other. And there the action ends. The only thing you can do is to press the bolt down and THAT is when the rifle goes into half-cock.

At this point the rifle is in absolutely SAFE mode. All you can do is to withdraw the cocking piece and shoot again.

Has that answered the question? I should add that if you were in a classroom as an Armourer apprentice, there'd be a LOT more to the actual mechanics of the matter than that simple explanation. At this point you can understand the vital safety importance of the safety stud on the bolt and the unlocking stud on the cocking piece

[Maxwell Smart]

It is to do with an extra element of safety, such as preventing the rifle firing if the bolt is not completely closed.

This topic is covered in some detail in a thread from 2010; if you use the search function and type in "Cocking Piece Difference" the thread in question should be found.

The replies from Peter Laidler and Bruce in Oz in that thread explain it better than I can.

(Added later - Peter is on the ball, his reply has already been posted above)

[skeet1]

Thanks Peter and Max I will check it out further with what you have said in mind.

Ken