303 British Chamber Diagram

[Alan de Enfield]

I found this one with the help of Google. Anyone have a better one?

If it any help this is the one published in the book "Textbook of Small Arms 1928"
It is the military dimensions of the cartridge and chamber.

Note - non of this 'namby pamby make it thin' requirement as per the SAAMI drawings 0.064" +0/-0.01" (military requirement for case rims was 0.058" to 0.064")




And the chamber dimensions from the 1943 dated blueprints (engineering drawings) for the No1 Mk3 which I think you have already seen.


I have the set of fully dimensioned drawing of every part and component of the No1 Mk3 but they are too large to post on the forum.

A 'small fraction' of one of the series of drawings :

https://i.postimg.cc/s2v2ZCWS/No1-Mk...mensions-2.png

https://i.postimg.cc/rFrCx7SB/Screenshot-2292.png

[Bruce_in_Oz]

"Mil-Spec" .303 chambers are just weird.

From the very beginning to at least the No4 days, they were NOT cut using "modern-style", one-piece 'reamers.

They were cut using a series of odd little short reamers, one for each "feature" of the chamber. There was a =n associated set of gauges used to measure each different stage.

The best bit is that final "setting" of the chamber was achieved by firing a "special" cartridge closely related to a "proof' round, to settle the insides of the chamber AND "final seat" the barrel, bolt and body assembly. Remember that all of those Lee Enfields were made from various grades of metal ranging from glorified "mild steel" to malleable cast iron.

I will see if I can find the full description of the process in my tree-ware files.

Let's face it: NOBODY was expecting to be reloading the "once-fired" brass, especially on the two-way range. As long as the brass case sealed the pressure in the barrel and was then extracted in one piece, NOBODY cared.

And then, there are all the "surplus" rifles that have had their chambers"freshened-up" for commercial sale. On a rimmed case this is bad enough, but when you start seeing WW2 Mausers with a millimetre of headspace BEYOND the "No Go' gauge, sphincters start to twitch.

The past is an "interesting" place.

[Alan de Enfield]

There is an excellent booklet (63 pages) that explains the manufacturing process of the Lee Enfield barrels. It is a 'modern' compilation of a series of articles ("Machining The Lee-Enfield Barrel - Operations and Fixtures Employed" written for 'Machinery Magazine' & published in 1916.

Booklet called "Making Rifle Barrels" and is ISBN 1-55918-280-6 Reprinted by Lindsay Publications in 2002.

Example of a couple of the many pages on the chamber :

Edit apologies that the pages are on their side - I cannot seem to be able to rotate them.

[Surpmil]

Allow me.