Info for Alan de Enfield (and all others)

[Edward Horton]

Alan

Lower on this page is some information from our leading American Ballistic testing laboratory “The H.P. White Laboratory Inc. I have never posted this information before because the term "Inherent Weakness" bothers me when talking about the Enfield Rifle BUT the information below applies to all firearms no matter what country they are made in.

“H.P. White Laboratory, an Intertek Company, is the leading small arms and ammunition research, development and testing laboratory and the only true independent ballistics testing laboratory in the country.” (The United States)

HP White :: Home

Alan the information coming from the U.K. that you and others have been posting about 7.62 NATO bullet weights and the No.4 Enfield, specifically the British 144 grain load puzzled me. This is because the chamber pressures for ALL bullet weights in a given caliber are set at the same approximate chamber pressure. And to be blunt I thought this bullet weight limitation was so much garbage.

The last article you posted here about water on your ammunition or in your chamber I also thought of as misinformation but I was re-reading some of the material I collected about oil or grease in your chambers and found the following information from the H.P. White Laboratory.

The key words in this information below is “cumulative effect” and “reducing the ultimate strength of the assembly”.

Excerpt below:

"1.4 Failure of a gun assembly from internal pressure may be from either
of two (2) failure mechanisms.

1.4.1 The general perception is that those failures are the result
of a single exposure to a CATASTROPHIC PRESSURE level. This
may be an over simplification in that the strength of the
assembly may have been degraded by previous repeated exposures
to excessive, but lesser, levels of pressure whose cumulative
effect is to reduce the ultimate strength of the assembly.

1.4.2 Repeated exposure to pressures which exceed the elastic limit
of a material will continually reduce the ultimate strength of
the material until the ultimate strength is exceeded by a
relatively low pressure level causing fatigue failure."

http://www.hpwhite.com/uploads/file/101-00.pdf

I have more to say but I will bring this up latter in this posting after a little feedback and discussion.

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[Edward Horton]

Is there a reason this posting is being moved to another forum when it supplies additional information relating to two separate postings in this forum by Alan de Enfield below?

(Alan de Enfield) More Bad Press For The Enfield
More Bad Press For The Enfield - Military Surplus Collectors Forums

(Alan de Enfield) NRA RE-Issues Enfield 7.62 Warning (Jan 2010)
NRA RE-Issues Enfield 7.62 Warning (Jan 2010) - Military Surplus Collectors Forums

[jmoore]

"Fatigue failure" here I don't think would of huge concern as unless the action is under strength enough to have a failure in a few thousand cycles, then merely changing bullet weight or for that matter, cartridge, would not move the probable failure point upwards by any significant degree.

Generally, acceptable "f.f." limits are set at the 100,000s or (10)6 cycle level to be considered safe in most stressed structures. Mostly because the failure point is hard to define w/in a factor of ten or so due to other variables that influence each individual unit. (Modern computer modeling can help here, but still!)

Additionally, microcracking is almost always started at or near the surface, so dye penetrant or magnetic particle testing can be used to check for problems well before total failure occurs.

So, if you're worried, get it checked. However, past history IS a good indicator of future performance in this case, so I believe fears from this failure mode to be groundless. I think regular old wear will render the rifle U/S before this point.

[jmoore]

One rifle that seems to have an unusually low "fatigue life" is the FAL et al.

Seem to remember published failures being noted starting at roughly the 40-50,000 round limit. Life was doubled by changing the method of producing the raw receiver, but I 'll have to go back to Stephen's book and refresh memory.

M9 pistols suffered from a horribly low life limit, but it was discovered early in its life cycle, so changes were made. No such drama was associated w/ any of the Lee Enfield derivatives of which I'm aware.


ETA:

Another example. Early Glock 17 slides would fail through the ejection port RH side at around the 100,000 to 125,000 round mark, invariably cutting across the post finish (and hardening step) proof mark. Moving the proof raised the failure point to roughly 250,000 rounds.
The point here is that the load path, Although a bit more assymetrical than a No4, is similar in concept. The pistol would CONTINUE to function even w/ the RH side completely fractured, although POI tended to shift.

[jmoore]

More thinking whilst running the machine:

Probable failure order of a No4's structural components:

1.Bolt head-
A)first excessive overturn (common)
B) then, fracture at the thread terminus (No No4 examples on hand, but I've several SMLE bolt heads broken off at this point.)

2.Bolt -
A) Forward face wear takes out most of these, I think.
B) Also the small lug in the striker cam area sometimes fractures- seen a few of those.
C) Bolt lug wear
D) Bolt lug shears off LH side - Never seen or heard of it though!

3.Receiver Body-
A)Bolt lugs wear through the hardened mating surfaces- Caught upon inspection- no real danger here.
B) Fatigue failure of RH receiver rail. Rifle contiues to function-sort of -probably begins to bind up on cycling and POI/accuracy go out the window.
C) LH receiver wall fails- a bad day! But there ought to be all the warning signs above.

Pure speculation, though. Tear this argument to shreds if y'all wish!

[Edward Horton]

I posted this in the Enfield forum as additional information to Alan de Enfield’s posting of the shooting article about firing the Enfield Rifle in the rain.

Water, oil or grease in the chamber increases bolt thrust and the repeated effects of doing this will damage any rifle as explained in the in the H.P. White article.

I’m posting this information for several reasons, below is a PM (email) sent to me asking for the possible reasons why this individual had to pound the bolt open and use a cleaning rod to remove every fired case from the chamber of a No.4 Enfield converted to 7.62 NATO.

Below is a photo copy of the PM sent to me.




Another reason is the photo below, it was posted in the old Gunboards forum by Norton47 who was a machinist and manufactured a longer bolt head to keep the primers from backing out of his newly acquired Turkish No.4 Savage. Norton47 had fitted a new bolt and a #3 bolt head and the primers were still backing out of the primer pockets of his reduced cast bullet loads.

A Turkish Enfield has no British Nitro proof marks and they were never touched by a trained British or Commonwealth Armourer. If any of you follow Mr. Laidlers postings you will remember common bolt heads longer than a #3 were not made due to the fact that by the time a #4 bolt head was needed the heat treating had worn through the bolt lug contact areas of the receiver and into the softer untreated metal.

In my opinion this Enfield should not have been sold here in the U.S. they are sold as antiques and curios and by law they are not required to preform any functional or safety checks of the firearms they sell unlike what is required in the U.K.



The following was printed in 1946 in Jim Sweets “Competitive Rifle Shooting”.

Number 66 is one of the allowable items from Australian shooting regulations.



A “Notice Warning” from the book.



From the same book on possible causes of barrel vibrations dealing with accuracy.




Don’t shoot the messenger but water, oil or grease in the chamber does not increase the life expectancy of any rifle, and trained Armourers stopped checking these Enfield a very long time ago (and some were never checked)

From an American Lyman reloading manual.



From the United States Military.

[jmoore]

Reduced power loads often back out primers as the primer upon ignition pushes the case forward, but there is not enough pressure (or the case grips the chamber walls) to "reseat" the primer. I've seen this in plenty of other rifles (w/ good to tight headspace) than Enfields, as have you, I suspect.

You still haven't figured out why this thread is "out here"?