7.62 Enfield question for Mr. Laidler

[Edward Horton]

Forgive me if I was asleep during one of you classes Mr. Laidler but did any of the 7.62 receivers on the No.4 Enfield up through the L42 7.62 get any special or different heat treating methods than a standard grade .303 No.4 Enfield receiver did.

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[Peter Laidler]

Short answer Ed is NO! There was no need. BUT, many of the old and tired No4T's passed(?) the 19T proof but were failed subsequently because the bolts were difficult to lift/open. This showed that while they 'passed' proof (?) the extra loading had proved too much for the sometimes marginal hardening of the locking surfaces.

I never quite fathomed out why the bolt would prove difficult to open in these such cases. Any ideas Ed?

Better just clarify that. Subsequently failed proof was as a result of the difficulty in raising the bolt lever immediately after proof and not subsequently, as in after years in service

[Alfred]

Short answer Ed is NO! There was no need. BUT, many of the old and tired No4T's passed(?) the 19T proof but were failed subsequently because the bolts were difficult to lift/open. This showed that while they 'passed' proof (?) the extra loading had proved too much for the sometimes marginal hardening of the locking surfaces.

I never quite fathomed out why the bolt would prove difficult to open in these such cases. Any ideas Ed?

Better just clarify that. Subsequently failed proof was as a result of the difficulty in raising the bolt lever immediately after proof and not subsequently, as in after years in service

Earlier when speaking of DP rifles with warped action bodies you said those may have been the result of the rifles being used as a step up when scaling walls in training. That method of helping guys over a wall goes back to the days of the halberd at least. M16 rifles sometimes broke at the hinge when this was tried.
Anyway I wonder if those rifles had been DP'ed because the bolts already binded in the body, due to either failing a re proof or use of MkVIIIZ ammunition or degraded MkVII ammunition.
Greener's book on "the Gun and its Development" tells of early Enfields suffering Jugged Chambers (not the words he used) preventing extraction. Other works on the Enfields of the pre WW1 era also mention excessive pressures damaging both Enfields and Sporting rifles when Cordite was used in tropical heat.
So far I haven't seen any Enfield bolts that were visibly warped but I did run across one Indian SMLE that had barely discernable ripples down the bolt body. These could be felt when cycling the action slowly and as the tarnish wore they became visible.

I'd like to hear more on those L42 rifles that suffered damage in service.

As for cartridge brass the alloys used for proof test cartridge cases can withstand much higher pressures than common cartridge brass, some US military proof test loads used in destruction testing of new designs (such as when the Garand was first being tested) went up to 120,000 CUP.

Whenever a metal object is mass produced on the scale of WW2 weaponry there will be slight variations in the strength of individual specimens.
Authoritative works on the Enfield written during its development put the figure of 20 tons cartridge operating pressures as the danger zone for the design.
The No.4 should be stronger than the earlier No.1 but how much stronger?

Apparently some destruction testing went up to thirty tons, but I don't think anyone considered this a indication of the ultimate strength of every rifle produced.
breaking strength of the receiver is quoted as 85,000 PSI, but whether this was arrived at by firing a overload or by hydraulic piston is not clear. This seems to be the maximum pressure the action body itself could withstand without breaking in half, or suffering other irrepairable damage.


Whenever a receiver of any sort is re barreled its original proof testing is no indication of whether or not the rifles has been subjected to even higher pressures at some point in its career through obstructions or defective ammunition. Replacement of bolt heads and bolt bodies to put the rifle back into trim might leave the gun appearing fine but with hiden problems, especially since bolt heads were swapped out between rifles and used bolt heads remained in inventory. No way of knowing whether or not the rifle a used bolt head came from was trashed by a overload, perhaps compromising the bolt head.


A final question for Mr Laidler.
Was there a specific type of cartridge aproved for use in the L42 rifles and were there ammunition types prohibited for use in these rifles?

[JBS]

Mr. Laidler, you have me puzzled now. I would expect the bolt to lift hard or very hard after firing a proof round. The yield strength of the most common cartridge brass is about 60,000 psi +/-. I would think that the brass would flow load the bolt a great deal making it hard to lift. The tester did not use the lug set back measurement method ?

[Edward Horton]

On the .303 Enfield’s two proof rounds were fired, one dry cartridge to proof test the barrel and one oiled cartridge to seat the locking lugs and bolt head. The oiled proof cartridge exerts twice the force on the bolt face, bolt head mating surfaces and locking lug contact area on the receiver than a dry proof or normal cartridge.

After proof testing the .303 Enfield was checked with a .067 head space gauge and if the bolt closed on this gauge the rifle failed proof testing due to excessive bolt set back.

If a three year old hit you in the jaw you would be able to tell the three year old that they was being bad, if George Forman hit you on the jaw and after you picked yourself off the floor you would have a hard time just moving your jaw let alone talking.

To the best of my knowledge NO American commercial firearms manufacture uses oiled proof rounds to test their firearms due to the severity of this type of testing. This to me speaks very highly of the British system of testing their Enfield Rifles before handing it to a British soldier to use in combat.

The problem is sometimes the Enfield rifle didn’t like getting hit by George Forman and the bolt was hard to open.

I was going to say Bah Humbug about Enfield inherent weakness and to never fire ammunition that has been oiled or greased but I don’t want to anger Badger and the moderators again and be hit on the jaw and then severely chastised.

[Badger]

I was going to say Bah Humbug about Enfield inherent weakness and to never fire ammunition that has been oiled or greased but I don’t want to anger Badger and the moderators again and be hit on the jaw and then severely chastised.

Thanks Ed ...

Good to see we're slowly making progress ...

Regards,
Badger

[Edward Horton]

Thanks Ed ...

Good to see we're slowly making progress ...

Regards,
Badger

Thanks Badger, I’m taking a weeks vacation in Canada next spring and I’m going to try hard not to be deported, I may even drop by and see you.
(Make sure all you Canadians lock up your Enfield’s)

[Badger]

Thanks Badger, I’m taking a weeks vacation in Canada next spring and I’m going to try hard not to be deported, I may even drop by and see you.
(Make sure all you Canadians lock up your Enfield’s)

You're safe Ed, we don't even deport Al-Qaeda here. We give them free universal health care, a monthly welfare check and try not to offend their sensitivities in our left wing propaganda newspapers.

Anyway, let's NOT get started on politics here, but if you're up this way, I'll gather up a few local members and you're welcome to drop over for a BBQ.

I've been trying to get Brian and Peter to come over and stay for a visit, so we could make an Enfield party of it, pawing over the wife's collection...

Regards,
Badger (Doug)

[Peter Laidler]

I think that Ed has answered my querie with as good an example as we'll get. It seems as though that while the barrel and bolt passed proof and the body APPEARED to have passed proof, the new re-proof load was too great for the hardened bolt locking surfaces within the body. As a result, the rifle was withdrawn, stripped and scrapped.

We have already had some superb pictures of the induction hardening spots on the No4 body so from the comments above, if the bolt lugs had recessed the now not-so hard- surfaces, that would answer why it was difficult to lift.

There were also problems in-service with hard extraction in the L42 too. But more about this later......

[Edward Horton]

As some of you know I would never think of beating a dead horse but with what Mr. Laidler has stated above I hope you see the reason for never shooting oiled cartridges.

You would be more than doubling the wear and tear on your Enfield’s locking lug recesses for NO good reason.

JBS

Below is a link to Varmint Al’s web page, you can find the different grades of brass and the effects of case-chamber friction and bolt stress.

Rifle Chamber Finish & Friction Effects on Bolt Load and Case Head Thinning Calculations done with LS-DYNA

I asked this heat treating question for a very good reason, I wanted to find out how many forum members here find it entertaining and fascinating to read or gather boring technical facts in obscure manuals that has nothing to do with collecting Enfield Rifles.

(But it does have something to do with the care and feeding of the Enfield’s you collect)