Lee enfield bolt fitting

[Alan de Enfield]

What is the differences in metallurgy between the Ishapure Smle and the British/Lithgow Smle? Why was the Ishapure stronger?

I'm afraid you have been misled by 'internet facts'.

The truth is that the Ishapore No1 Mk3 is actually manufactured from inferior steel and rather than 'lose-face' and revert to the 'proper' steel grades they decided to alter the proof testing to get it to pass.

The 'full story' was published many years ago by the Ishapore Proof Master, but there are some forums and information sources that say he is wrong. (One of the main proponents of the 'false information' is a forum that supports the fact that the chambers of the No5 Mk1 rifle were made oval to allow the water from the tropical monsoons to drain down the barrel & out past the round)

The article covers a host of subjects (and several pages) based around the Indian firearms industry and more specifically the ‘Proof House’, but of particular interest are a couple of paragraphs regarding ‘Enfield’s’.


Extract from “Gun Digest 33rd Anniversary 1979 Deluxe Edition”
Article Author : Mr A G Harrison
Qualification : Former ‘Proof Master’ of the ‘Rifle Factory Proof House, Ishapore, India’

From 1908 to 1950 all military bolt action rifles made at Ishapore were proof tested with a dry-round, followed with by an oiled proof round (as per UK military requirements). The proof cartridge was loaded to 24 tons psi breech pressure, or 15% higher than the service pressure. In 1950 (after the departure, in 1947, of India from British control) the material for the rifle bodies was altered from an EN steel to SWES 48 steel with the recoil shoulder and cam recesses being heat treated. With this change the rifle receivers distorted when oiled proof cartridges were fired. This was discovered when hard and sometimes impossible bolt retraction was experienced. Large quantities of rifles were rejected.
To avoid rejections the authorities ordered discontinuance of the oiled proof round. Therefore from 1950 to the end of SMLE production, rifles made at Ishapore were proof tested with one dry proof only, although the specification still called for both dry and oiled proof. All bolts and bolt heads issued as spares were always proofed with a dry proof round only.


Although you asked about the 'SMLE' a little bit more infortion was provided by the Proof Master about the SMLE derivative - the Ishapore 2A & 2A1 which were built on the SMLE action.

They first manufactured the 2A using the same steel as they were (now) using for the No1 Mk3 and it was an unmitigated disater as it was unable to withstand the forces of the 7.62 round, and warped, twisted and totally 'locked up'. Ishapore then decided to (save face) and announce they were using a 'superior grade' of steel, when in fact, what they did was actually revert back to the original British specified EN steel for the 2A, although the manufacture of the No1 Mk3 retained the SWES steel and all the No1 Mk3s were tested under the new proofing regime.



Never believe anything you see on the internet unless it is supported by either period documentation, or written by those personally involved in the subject.

Information

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