No. 4 Rifle; Zeroing Instructions Data Inconsistency?

[Surpmil]

Interesting that other period documents warn of the effects of firing wet cartridges, and note that the SMLE has been known to fracture on the left hand side from the additional, unequal, pressures.

Curious that the second text states that "...in extreme cases the action body has been known to fracture..." Presumably they meant to say the bolt body.

The test done at Enfield wherein an unthreaded barrel inserted into an unthreaded body/receiver, with what we assume was a relatively close slide in fit, fired normally with absolutely clean chamber and ammunition, but was blown out of the rifle if there was any oil on either chamber or cartridge case is detailed at the top of page 270: Textbook of Small Arms 1929 [Great Britain War Office] : [Great Britain] War Office : Free Download, Borrow, and Streaming : Internet Archive

I would assume also that the barrel and body were not so close a fit to each other that the barrel itself expanded and adhered to the body during that test.

[Alan de Enfield]

Curious that the second text states that "...in extreme cases the action body has been known to fracture..." Presumably they meant to say the bolt body.

No, I don't think so - In the past I have read reports of SMLE sidewalls fracturing.

I think the examples of fractured bolts has generally been found to be poorly cast (granulated) steel in the bolt body.

[Rick]

MkVI vs MKVII is another subject :
comparison in trajectories of MkVI & MkVII

Alan, that off-topic subject is dangerously close to sending me down yet another military pam rabbit hole unrelated to conflicting zeroing instructions.

So if the potential enemy infantry of 1929 was apparently 5'3" in height... what are they today, almost a century later?

And if that potential enemy were seated on horseback as calvary, now the top of their heads are only 39" higher? How many hands height were cavalry horses back then? Short legged little compact ponies? Seems a fair question because I never rode a horse back when I was growing up on our place where the stirrups were either even with the top of the horse's femur or the same height as my instep at the crotch.

And then there's the difference infantry company/platoon/section commanders would consider between the two regarding beaten zones and first catch/first graze.[quote=Alan de Enfield;547175]No, I don't think so - In the past I have read reports of SMLE sidewalls fracturing.

---------- Post added at 03:38 PM ---------- Previous post was at 03:32 PM ----------

No, I don't think so - In the past I have read reports of SMLE sidewalls fracturing.

I think the examples of fractured bolts has generally been found to be poorly cast (granulated) steel in the bolt body.

Alan; fun personal trivia... when a friend bought the remnants of the failed Montana Rifle Company, compete with both modern Haas five axis CNC machinery and surplus Springfield Armory WWI Pratt and Whitney gun drills and reamers, I worked for him for a few months as the ops manager to sort through the chaos and get some simple manufacturing and cash flow going.

While sorting through the carcass for any and all useful information, I went through the Customer Service files. In some of those complaint letters from purchasing of Montana Rifle Company's reworking of the classic Model 70 action, were letters relating to cracked receivers and bolt lugs. Those receivers and bolts were made on very, very modern machinery in that facility, from modern bar stock and castings, and then test fired with proof rounds and then inspected again before shipping.

In the case of the cracked receivers, I later found out that MRC was getting shipments of castings where some were misshapen - some to the point of almost resembling a banana. Rather than reject them and request replacements (and better QA/QC), MRC had their machinests muckle together some jigs, and then trained a couple of eager, conscientious young employees to use a hydraulic press and an array of dial indicators to bend those crooked castings enough so that they could be fitted into the tombstones of their CNC machines and then machined into a finished receiver. They then shipped them back across the country to have the heat treating and hardening redone to be as it was when the castings were received.

You don't have to be a machinist nor a genius to realize that machining those imperfect and still crooked blanks would invariably result in thin and thick parts at various points in the finished receiver. Nor stress points induced from being reshapen in a 20 ton hydraulic press.

BTW, they also fired their head machinist and CNC programmer (a brilliant guy they hired away from the aerospace industry) because he told them the problem with the receiver blanks was mould slump in the castings. Later on, a rep from the company that did the castings came around, looked at the castings that resembled bananas, and said it was mould slump... no wonder they went T-U when being run by that boutique consortium that purchased MRC from the original owner.

So that's circa 2018... I can easily imagine all the various possibilities that could result in failure from poor castings a century beforehand, manufacturing under the pressure of WWI conditions.

[Alan de Enfield]

So that's circa 2018... I can easily imagine all the various possibilities that could result in failure from poor castings a century beforehand, manufacturing under the pressure of WWI conditions.

A couple of pics of fractured No4 rifles