No4 Bolt head question

[Alan de Enfield]

I'm beginning to wish I'd never started - I'm now lost deep inside the rabbit hole metropolis and I didn't leave a trail of crumbs to find my way out.

I now find that there were actually dummy bolt heads increasing in small increments so you (the armourer) could identify exactly what size the headspace was and select a bolt head of the necessary dimensions, non of this 0.064" - 0.074" "it passes" malarkey.

From an old wayback internet for sale advertisment :

This is a Lee Enfield No.1 Rifle ( SMLE) inspectors dummybolt head gauge. Very nicely marked 'GAUGE INSPECTORS DUMMYBOLT HEAD .639" IN SM153 CIA' Dated 1951. These gauges were issued in sets of various lengths ( this one is .639" ) and used in conjunction with headspace gauges to determine the correct bolt head needed for the No.1 rifle. As they are not threaded, they are easy to slip in and out of the bolt without removing it thus speeding up the process. Once the correct length was decided, the inspector would fit a corresponding sized bolthead. I have several of these, but unfortunately they are all the same size. In excellent condition, an interesting collectable.


Sure enough it is listed in my "No1 Gauges and Inspection book"

[Alan de Enfield]

I no longer have the option to edit the post on the SMLE bolt head overturn, so a bit out of sequence but some more information :



There is indeed a 'bolt head overturn gauge' listed in the book of gauges.

SM402 15" Mk2. Use : to measure the bolt head overturn.





On a later page it shows how it fails and the bolt head is rejected if it hits the 15 degree mark






The bolt head overturn gauge for the No4 rifle is part number SM390 and is used in a similar way except that the gauge is marked with 20 degrees