No4 Bolt head question

[WanderingKiwi]

I am sure that, over the years, this question must have come up but I can't find it in the forums:
Is there a technical reason why an No4 bolt headspace/clearance can not be adjusted by adding a shim behind the bolthead?

[Alan de Enfield]

I am sure that, over the years, this question must have come up but I can't find it in the forums:
Is there a technical reason why an No4 bolt headspace/clearance can not be adjusted by adding a shim behind the bolthead?

1) Moving the bolt head forward means the striker will now not be long enough.

2) It is very poor engineering practice.

3) The official answer is :"If headpsace cannot be achieved using existing bolt-heads then it is the body that is scrap. Typically the hardness has worn thru' on the body locking lugs and every firing / recoil pushes the bolt locking lugs further and further back and no bolt head can accomodate that"

[Bruce_in_Oz]

The striker protrusion is set by the overall length of the bolt-head . (Given "consistent" striker dimensions)

Furthermore, when the action is closed for firing, the bolt-head is set to transfer ALL of the thrust od the cartridge head DIRECTLY to the front face of the bolt body, and thus to the locking surfaces. The bolt-head THREAD should play NO part in transferring this thrust.

This is why bolt-heads are "paired" to their bodies in the final assembly. If the bolt-head "under-turns", the bolt CANNOT be assembled to the body. Get another one out of the parts tray.

If the bolt-head OVERTURNS more than a few degrees, The threads will start being battered at every shot and headspace will thus start to grow.

Lee Enfields are NOT "shake and bake" rifles.

There are copies of the "official word" on this matter out there on these Inter-Tubes.

How many variables can dance on a Km7 bulllet meplat?