Peter: seen this low axis pin on many No4s?

[RJW NZ]

Did Thunderbox ever supply a measurement from the top of the ear the the base at the plunger hole? I got to quit coming here, the more I read, the less I know. That is an odd duck.

I'm sticking to my observation on my no1 mk6, that the rear sight pivot is set up lower because the receiver was intended for a different detent system, ie ball and spring ala no1mkv 1922 ish, and that the later system requires a bit more room because of that flat head on top of the plunger.

As for people discovering this on rifles other than the mkV and mkV1, my educated guess is that they are prefix A marked receivers from the early era that were put back into the system.

I keep pointing this out but never hear a comment from anyone in acknowledgment.?

I'll come back to this post with pics and measurements in an hour or so.

Here's the skinny
My 1955 measures .3795 (ie 5 under .380) from the top of the sight axle to the deck of the receiver beside the plunger hole.
The 1930 measures .310 in the same place.

The difference = .0695

(The thickness of the cap on the plunger is .05, so its not an obvious connection.)

Plungers also do not fit the 1930 unless I dremel the diameter down a bit, that hole where the spring lives is definitely narrower than on later enfields, no plungers I've tried will fit without modifying them first.