Bolt HeadcFitting Question

[Alan de Enfield]

I am assembling a new bolt head of matching #0 as insurance against leaking Winchester 41 primers. The one obtained looks new of finish, and doesn't look like it will line up with the rib without some help.

I understand there was a tool for helping bolt heads fit. Have no such tool and suspect they are not common.

Asking if anyone has a preferred technique they can share for helping a new bolt head to rotate fully onto a bolt body.

Firstly you do realise that not all number '0' bolt heads are the same 'size', '0' is not a size it is just a number. I have seen a number zero bolt head of 0.616" and as big as 0.636" so 20 thou difference between them, the nominal 'cluster' of size zero (it is a bell-curve) is between 0.626 and 0.631, still 5 thou, which could make a big difference if your headspace is towards the top end of the spec.

How did you determine that you wantd a number 0 bolt head ?

Regarding getting it to 'clock' correctly the tool was used if it was just a few thou off being correct, some bolts / bolt heads would just not align as the start point of the threads can be 'anywhere'.

If you read Peter Laidlers notes on bolt head selection you will see that the Armourers would have trays with dozens of bolt heads and they would have to go thru them to find one that gave the correct headspace, and, the correct clocking. The chance of you buying one bolt head and it meeting all the criteria is fairly remote.