That proof thing, again

[Bruce_in_Oz]

I have excerpted notes from a January 1969 report from RSAF Enfield of a test they carried out, firing 75 x 7.62mm NATO oiled proof rounds through a No 4 barreled action 'without any serious damage to the body'.

Notes continue: "In the course of this test, two bolts were fractured, one on the 60th and the other on the 75th round, but that 'the bolt failures were such as would be unlikely to cause injury to a firer'. The military proof pressure used at the time, was 28 tsi radial, using one dry and one oiled proof cartridge per rifle. Clearly, this 'torture test' was several orders of magnitude beyond what any No 4 rifle would ever experience in routine use."

If anyone has a copy of the full report it would make an interesting addition to the technical library.

It is also worth adding that if an Enfield bolt head is cracked due to failure/overstressing, which is not that uncommon, it can simply be replaced with another, and that the main full-length locking lug on the No 4 bolt is quite massive." Not only that, but there is a hell of a lot of metal behind the locking shoulders in the receiver.

See what happens when the dainty little lugs or shoulders on "modern" rifles with no additional safety lug, unlike a Mauser, fail.

But wait, there's more!! P. O. Ackley did a bunch of tests way back when. With a SMLE action set up for .30-40 Ackley Improved, the following results were obtained:

57gn Hi-Vel#2 - 150gn ball projectile - High pressure, Primer OK
52gn 4198 - 150gn ball projectile - Leaky primer
50gn 2400 - ditto bullet - Bolt wrecked, receiver bent.

He noted:" When this action gave way, the receiver itself bent down at the rear, allowing the front end of the bolt to come up out of the receiver ring, thus allowing the bolt to be bent and to be broken. The locking lugs themselves did not give way".

Australian XP 7.62NATO No1 rifles were subjected to similar abuse to the No4 above, (and this is with receivers "modified" to accept FAL mags). The one I got to play with in the late 1970's had stretched a bit , again, more on the right than the left but had not shattered, . Not surprisingly, the project was abandoned: I suspect that factors of "logistics" and professional pride also contributed to this abandonment.

Information

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[Thunderbox]

I still don't think you're going to convince the doomsayers on this board..... LOL

[Alfred]

But wait, there's more!! P. O. Ackley did a bunch of tests way back when. With a SMLE action set up for .30-40 Ackley Improved, the following results were obtained:

57gn Hi-Vel#2 - 150gn ball projectile - High pressure, Primer OK
52gn 4198 - 150gn ball projectile - Leaky primer
50gn 2400 - ditto bullet - Bolt wrecked, receiver bent.

He noted:" When this action gave way, the receiver itself bent down at the rear, allowing the front end of the bolt to come up out of the receiver ring, thus allowing the bolt to be bent and to be broken. The locking lugs themselves did not give way".

I'd been looking for Ackley's tests involving the SMLE, his testing of other action types is more easily found.

Remember that the "NATO Proof Rounds" of that era generate little more pressure than the max allowable deviation of the M118 Long Range Special Ball.

Keep the pressure level of loads you chose to use within the safety margin of the action and you'd have no problems, that goes for just about any rifle and cartridge combination.

'the bolt failures were such as would be unlikely to cause injury to a firer'.

Serious injury or death due to shattered bolt heads or blown out boltheads that I've found references to were apparently to bystanders such as an officer instructor or where a shooter tried to testfire by holding the rifle away from himself.

It is also worth adding that if an Enfield bolt head is cracked due to failure/overstressing, which is not that uncommon, it can simply be replaced with another,

Unfortunately pieces of broken bolt heads have ended up in the internal organs or throats of those standing too close when they gave way.

and that the main full-length locking lug on the No 4 bolt is quite massive." Not only that, but there is a hell of a lot of metal behind the locking shoulders in the receiver.

Yet those massive ribs can be assumed to have bent and/or broken along with the rest of the bolt body.

I suspect that factors of "logistics" and professional pride also contributed to this abandonment.

The only supposedly official reason I've heard of was that the rifles would have had too short a service life to be worth the effort and expense of conversion.
If a rifle has to be babied to insure that it won't fail in combat thats not a good sign.
Battle rifles are expected to continue to operate under the worst conditions with no more maintenance than a beleagured trooper can give it when he himself is short of the basic necessities of life.

I still don't think you're going to convince the doomsayers on this board

Chevalier attitudes towards gun safety don't help the sport.

I expect that the gentleman who required reconstructive surgery to repair his crushed and torn genitals after the magazine of his 2A rifle blew out would have done better to have limited his shooting to ammunition that generated pressures no higher than the rifle was designed to handle.

[villiers]

So, all that hot air and the end result is a platitude:

"Keep the pressure level of loads you chose to use within the safety margin of the action and you'd have no problems, that goes for just about any rifle and cartridge combination."

[tiriaq]

Loss of containment of powder gases, with associated fragments of brass, etc. is a real safety concern. Bolts seldom get blown out. It is the catasrophic case failure that can do harm.
Some actions like the Remington 700 will protect the shooter. Others won't.

Yes. Use appropriate, quality ammunition in a rifle in good condition, and unfortunate incidents are unlikely.

[Peter Laidler]

In all of my service, albeit very limited and sheltered, from 1963 to date, I never saw a breech explosion in a small-arm but had one 'doctored' as an explanation and heard of two at close hand and those two were explained in detail on the Joiuster site.

I would assume from that, that the trusty old bolt action Enfields, their Brens, GPMG's and pistols are pretty safe...................

[Alfred]

So, all that hot air and the end result is a platitude:

"Keep the pressure level of loads you chose to use within the safety margin of the action and you'd have no problems, that goes for just about any rifle and cartridge combination."

Platitude?
Hot air?
How about ignoring basic gun safety and ending up with a face full of "hot air" at temperatures that can melt steel?

I take safety seriously, some who read these forums may be entirely new to the shooting sports or hand loading.
Some new guy may see claims that lead him to believe that his WW1 SMLE can safely handle loads of 62,000 psi, and maybe even get away with it for a few test shots , then have a Kodiak moment on YouTube that sets back the sport by decades.

tiriaq writes

Loss of containment of powder gases, with associated fragments of brass, etc. is a real safety concern. Bolts seldom get blown out. It is the catasrophic case failure that can do harm.

And bolt body compression or warpage under excessive pressure can lead to the case being blown out. In the few recorded instances of bolt head failure I've been able to find the pattern of destruction leads me to believe that the ruptured case allows some of that "hot air" to blast into the cut out for the extractor sending the extractor at high velocity out to the right hand side.

Some actions like the Remington 700 will protect the shooter. Others won't.

The Lee actions seem fail in a manner unlikely to directly endanger the shooter, but bystanders bleed also.

Yes. Use appropriate, quality ammunition in a rifle in good condition, and unfortunate incidents are unlikely.

I hope the repitition of "platitudes" doesn't upset Villiers or Thunderbox too much.
I wouldn't subject even a high number Springfield of WW1 or shortly afterwards vintage and metalurgy to the highest acceptable pressures of some sporting .30/06 ammunition available today. Those actions given the dual heat treatment were considered the strongest ever made at the time, but age and hard use can take its toll even on steel.

We can assume that the Spanish model 93 rifles converted to 7.62 were proof tested at the time of conversion, but I would not suggest feeding one of these a steady diet of M118 LRSB or the hottest of .308 loads either.
The Model 95 actions converted to 7.62 at least have a safety lug, but that doesn't make them a stronger action, just less likely that the bolt would blow out if a round generating excessive pressure due to any of a number of factors were to over stress the action, or age and metal fatigue finally caught up with it.

Those Indian No.1 .303 and possibly some 2A 7.62 rifles manufactured from SWES steel up until the mid sixties were never even properly proof tested for the .303 and 7.62 NATO ball available at the time much less the hottest long range loads of today.

[Alan de Enfield]

Here we go again, weak actions, exploding bolts etc. etc.


Use what the Rifle is designed / proofed for and you wont have any problems. If its a 303 use Mk7 type ammo or load to Mk7 specifications. Its been proofed to that.
If its a 7.62 then use standard mil spec 7.62 or load to that specification. Its been proofed to that.

If PL has 50 years of experience (and 10s of thousands Enfield Rifles) under his belt and has never seen / heard of a failure (except the two that were fired without bolt heads) I reckon its "fit for purpose".

If you want, you can break anything - put a V8 engine in a Mini and the next weakest link in the 'chain' (gearbox ?) will blow up.

If you want 50 cal performance, buy a 50 cal !!!!

[jmoore]

Give it a rest, already. At least if you're gonna continue, go blow some stuff up! With Pictures! I've some barreled actions you can have (through an FFL). Just pay shipping. No1 Mk III's, that is.

[Alfred]

Here we go again, weak actions, exploding bolts etc. etc.


Use what the Rifle is designed / proofed for and you wont have any problems. If its a 303 use Mk7 type ammo or load to Mk7 specifications. Its been proofed to that.
If its a 7.62 then use standard mil spec 7.62 or load to that specification. Its been proofed to that.

If PL has 50 years of experience (and 10s of thousands Enfield Rifles) under his belt and has never seen / heard of a failure (except the two that were fired without bolt heads) I reckon its "fit for purpose".

A member of a sister site had just such a bolt head failure with a fresh from the wrap FTR'ed No.4 not so long ago. I remember he got a bit hot under the collar at blyth dismissals and the term "catastrophic failure" being tossed around. Had the rifle not be test fired remotely rather than from the shoulder things might not have gone so well.
Mr Laidler was not present when that rifle lost its bolt head. I expect that many action failures go unreported especially if they happened in combat where the victim might well die from exsanguination or shock without prompt aid or spend years in a prison camp should he survive.
The record of LE action failures in the Canadian house of commons debates includes a comment on these incidents having never been reported in the news papers.
Aside from use as a Sniper rifle I've seen no mention of converted No.4 rifles being used in combat. From the state of some Indian rifles I've seen I suspect that many 2A ended up being chopped up for parts long ago, with the best examples surviving to end up pulling light duty or as trainers.

As for Proof tested to 7.62 specs some 7.62 ammunition max deviation including M118 LR special ball exceeds the maximum allowable pressure set by the MOD for 7.62 ball and is very close to proof test pressures used by the MOD.

If you want, you can break anything - put a V8 engine in a Mini and the next weakest link in the 'chain' (gearbox ?) will blow up.

If you want 50 cal performance, buy a 50 cal !!!!

The point is that the gentleman whose manhood almost ended up as a medical curiousity exhibit in a jar somewhere would have profited by advice on what pressure levels would be safe for his rifle.

If I owned the finest J P Sauer Mauser sporting rifle of the 1930's I'd baby it with loads of less than maximum pressures.
I very nearly bought one of these dirt cheap some years ago, for 1/10 its present value. It was in an odd caliber or I'd have snatched it up, should have anyway. The rifle looked so modern that I'd thought it was a recent import, I later found it was a very old rifle with a stock especially designed to appeal to US shooters.
Even a rifle in such great condition as that one, and of proven strength and safety, deserved to be fed ammunition that would not cause excessive stress or wear.

There are early M98 style Mauser sporting rifles that were not intended for use with the higher pressure 7.92X57 ammunition thats available today. They may handle the hottest loads, and then again they might not.
The action type actually appeared in sporter form as early as 1896 with minor differences in contruction of the cocking piece and firing pin.

Just because a cartridge will fit the chamber is no gaurantee that the action was intended to use the hottest available loadings of that cartridge.
Recently I was discussing German LMG cartridges and their use in the K98. Years ago I got hold of some really jacked up AP rounds that had a muzzle blast so harsh I thought my Persian Mauser Carbine had exploded.
From a site on the German MGs I found that this was a special high velocity heavy bullet long range AP round that was loaded to much higher pressures than would be safe for the Mauser infantry rifle. The round was discontinued early in WW2 due to shortage of Tungsten for its extra heavy core so its seldom encountered. Problems might arise if a Mauser owner assumed that because later AP ammo for LMG use is considered safe in the rifles that all such LMG ammo is safe in the rifles.

A couple of months back I looked over a thread on another forum in which a young shooter described the appearance of fired cases from his No.1 rifle with cut off plate slot.
The base was cocked at an angle and cases cracked or separated on first firing.
The rifle looked normal at casual inspection.
It never occured to me at the time but I now suspect that his receiver was already cracked either below or above the cut off slot. Though there are other possibilities. In any event I'd consider that rifle unsafe to fire.

If an SMLE receiver can be cracked by firing a rain wet ball cartridge on the range, as a recently posted warning stated plainly enough, then its pretty obvious that the safety margin of the receivers had been compromised in some way that didn't show up in proof testing.

Standard 7.62 NATO ball is not a house afire hot load, but some other 7.62 NATO ammunition is loaded to pressures in excess of those of the MkVIIIZ already known to be unwise for extended use in the No.4 rifles and possibly dangerous in the SMLE.
Use of MkVIIIZ in the Infantry rifles was a case of emergency use only when ammo was in short supply. I don't think that sort of warning should go unheeded.

I'd be interested to know the pressure level of the .30-40 IMP loads that broke P O Ackley's SMLE action. The 30-40 Imp was designed to give .308 level ballistics from the rimmed cartridge and actions suited to rimmed cartridges.