AIA #4 clone proofing

[Son]

I've drilled holes in enough Lee Enfield receivers to doubt that they are case hardened.

The No1 MkIII receivers were case hardened in several places (not all over) mainly for the purpose of resisting wear or impact from moving parts. The locking lugs being one such area. In fact, the manual will tell you that the headspace check conducted with a test bolt body is to determine the amount of wear on the lugs. If a rifle fails headspace with it's own bolt, but passes with the test bolt fitted it can be repaired with replacement parts- (eg bolthead bolt body or both) If it failed both tests then the receiver was scrapped (hardened surfaces worn away or damaged/extruded) Funny thing that most don't realise- the spec for a NO-GO headspace gauge is set to fail an action (testing with the test bolt) for a worn receiver because the .004" wear is the approximate depth of the case hardening on the lugs.

All this just adds weight to Dimitri's point about tensile steels. To do the job, the receiver has to be elastic. That is, to be able to absorb certain forces and return to it's original shape. In doing that job, certain areas are subjected to impacts that would alter the shape, so they must be hardened to protect against it. Hardening the area effectively increases the surface area of the impact and reduces the effect.

I would be very concerned about the suggestion the receivers are all hardened steel... Hmmm... isn't there a lesson learned previously on the topic of receivers being too hard to the point of being brittle. What serial number early Springfields were they that were prone to cracking or shattering?

PS- (from further back) I think the Birmingham Proof Mark is alongside the factory stamp.

Information

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[ireload2]

I would be very concerned about the suggestion the receivers are all hardened steel... Hmmm... isn't there a lesson learned previously on the topic of receivers being too hard to the point of being brittle. What serial number early Springfields were they that were prone to cracking or shattering?

Maybe you might like to ask why the 700 Remington uses a through hardening steel for their receiver? This is not the early 1900s. A through hardening steel can be 32 RC or it can be 64 RC. Some can be heat treated almost anywhere in between.

[Son]

Maybe you might like to ask why the 700 Remington uses a through hardening steel for their receiver? This is not the early 1900s. A through hardening steel can be 32 RC or it can be 64 RC. Some can be heat treated almost anywhere in between.

Ok, I don't know why they use the steel they do... but I know why it doesn't matter a toss if they use kryptonite, cast iron or even cardboard.

The pressure bearing components- the bolt and the chamber- are locked together at the time of firing, so there is no force imparted onto the receiver at all other than the effect of recoil as it is transferred to the shooter's shoulder. Totally different for a rear locking action for example... Lee Enfield... where the pressure is restrained by the receiver from near the rear of the action where the bolt locks to the rear of the barrel where it is screwed into the action.

There are probably more firearms out there that use die cast aluminium or thin pressed mild steel sheet for their receivers than harder grades of forged steel. Maybe the Remington uses it to maintain high grade surface finishes and tight tolerences between moving parts- lengthening their servicable life and making them look pretty... nothing to do with controlling the chamber pressures.

AIA were very clever using a description like they do. It's put together to make people who have doubts about a real Lee Enfield taking full pressure 7.62 loads (and the associated stigma with rear lockers) feel better about their product... All they really did by enlarging the dimensions slightly and use of "milspec grade alloy" (gotta take your hat off to thier spin doctor!) was make it easier to machine and remove the need for heat treatment hardening of load bearing surfaces. DOUBLE WIN for them- cheaper to make with less skills required.

[Alfred]

I still haven't found any information on the exact alloy of steel used for Enfield Lock receivers.
I figure it just about had to be at least a mild Nickel Steel, nickel steel has excellent elastic properties and would be the best choice for a rear locking action. Its best that such a receiver strecht just a hair and snap back, probably less than one ten thousandth of an inch under a normal load.

Breaking strength of the earlier LE receivers was quoted by Ross as being 85,000 Pounds, but he didn't say if this was a test to destruction cartridge or whether the figure was from a mechanical or hydraulic application of force. I'm figuring hydralic testing, not sure why but that would fit in with some things I've read of 19th century methods in testing of such metal structures, especially ordnance breech mechanisms.

Considering the power of main battle cartridges of the period and up till post WW2 times, the actions of every sucessful bolt action rifle were remarkably lightweight.
The No.5 always seemed an odd duck to me, they couldn't have saved much weight from lightening the receiver, lighter wood or a composite stock and slimmer barrel would have done much more without weakening the receiver.

[Dimitri]

Care to elaborate on the contradiction with your statement above?

No its not, 4140 is heat treated the same way as the 8620. You first "through" harden the steel, but due to the low carbon content (0.40% hence the 4140) case harden the outside for a tough durable surface.

The inner core of 4140 once supposedly through hardened gives you a core of 35-40 Rockwell "C" scale, getting it to 45 or higher is practically impossible. Instead the core is heat treated to make it tougher but still retain elasticity, cause without that, the receiver will want to shatter instead of flex under the pressure of the fired round. Then the surface is hardened though "case hardening" which can be done with plain Carbon packing, Nitrogen based methods or a few other methods, to give you a hard outer shell of 55-65 Rockwell C to allow the receiver to last with little wear and tear from repeated firings.

Maybe you might like to ask why the 700 Remington uses a through hardening steel for their receiver?

They don't. Read my reply above. Through hardened steels are actually tool steels, with a high 0.50-0.95% carbon content that will allow the heat treatment into the core. All other steels will not do that 4140 is still just a mild steel.

Dimitri

[ireload2]

No its not, 4140 is heat treated the same way as the 8620. You first "through" harden the steel, but due to the low carbon content (0.40% hence the 4140) case harden the outside for a tough durable surface.

The inner core of 4140 once supposedly through hardened gives you a core of 35-40 Rockwell "C" scale, getting it to 45 or higher is practically impossible. Instead the core is heat treated to make it tougher but still retain elasticity, cause without that, the receiver will want to shatter instead of flex under the pressure of the fired round. Then the surface is hardened though "case hardening" which can be done with plain Carbon packing, Nitrogen based methods or a few other methods, to give you a hard outer shell of 55-65 Rockwell C to allow the receiver to last with little wear and tear from repeated firings.



They don't. Read my reply above. Through hardened steels are actually tool steels, with a high 0.50-0.95% carbon content that will allow the heat treatment into the core. All other steels will not do that 4140 is still just a mild steel.

Dimitri

Dimitri
I suggest you read more before you post. 4140 is a direct hardening chrome moly steel. When quenched the hardness goes all the way through. Once it is heat treated and tempered it is used as is with out carburization. There is no need to case hardened. If you Rockwell test a Remington 700 receiver you will find it is only about 40-44 RC and that is plenty hard enough for the application. I have 40XBR Remingtons and the receivers of those rifles are machined after HT so they will remain straight. If you are not going to post accurate information here why post at all?

[ireload2]

Ok, I don't know why they use the steel they do... but I know why it doesn't matter a toss if they use kryptonite, cast iron or even cardboard.

The pressure bearing components- the bolt and the chamber- are locked together at the time of firing, so there is no force imparted onto the receiver at all other than the effect of recoil as it is transferred to the shooter's shoulder. Totally different for a rear locking action for example... Lee Enfield... where the pressure is restrained by the receiver from near the rear of the action where the bolt locks to the rear of the barrel where it is screwed into the action.

There are probably more firearms out there that use die cast aluminium or thin pressed mild steel sheet for their receivers than harder grades of forged steel. Maybe the Remington uses it to maintain high grade surface finishes and tight tolerences between moving parts- lengthening their servicable life and making them look pretty... nothing to do with controlling the chamber pressures.

AIA were very clever using a description like they do. It's put together to make people who have doubts about a real Lee Enfield taking full pressure 7.62 loads (and the associated stigma with rear lockers) feel better about their product... All they really did by enlarging the dimensions slightly and use of "milspec grade alloy" (gotta take your hat off to thier spin doctor!) was make it easier to machine and remove the need for heat treatment hardening of load bearing surfaces. DOUBLE WIN for them- cheaper to make with less skills required.

Son
All you are doing is spinning your own tale without facts.
A Remington 700 action by design takes the full force of firing just as any other action two lug front locking action. The forces are taken over very short sections of high strength steel. All of these forces are absorbed by the relatively large sections of the receiver ring and the front lock lugs. These components are short and and are not subject to much stretching.
Rear locking actions have long sections subjected to the firing forces and subsequently stretch. It is not a stigma it is real. It is simply physics.
Because of the layout of the action it is a little quicker to operate but you pay a penalty in rigidity. When reloading cartridge cases you see a big difference in case life and the efforts required to COPE with the forces that cause case head separations.
Rather than spin the situation yourself why don't you find out what steel is used by AIA and the dimensions used by their receiver. Then analyze the receiver and find out what the difference is. I can tell you right now that the steel used will not affect how much the action flexes. That is governed by the modulus of elasticity (AKA Young modulus). Young modulus is about the same for ALL common steels. What does affect the flex is the cross section thickness of the receiver. The flex is reduced directly in proportion to the change in receiver cross section area.

[Son]

Son
All you are doing is spinning your own tale without facts.
.

I got a better idea- dispute this...

FACT
The AIA line of rifles are not Lee Enfields and therefore have no real place being discussed here other than perhaps a cursory mention as a passing oddity. They deserve even less space than the factory bubba jobs from Navy Arms, Gibbs, and other rifle chop-shops who at least started with genuine Lee Enfields. And before anyone gets all hot and bothered about the supply of milsurp rifles drying up, these chop shops were operating when the rifles were a dime a dozen- they were a fact of life then, but no longer get made now.
BUT AIA admit to using up supplies of genuine No4 spare parts to suppliment their production, and then have the hide to say their product is desirable because the genuine No4's are getting harder to come by. PLEASE! They are helping to create the shortfall of available milsurp rifles that they are advertising as being an alternative to.

Bottom line- pay many hundreds of dollars for a rifle that will never be a Lee Enfield- possibly not permitted in competition and at best a poor excuse for a target rifle anyway- it will decrease in value from the time you fork over your hard earned cash.
May as well buy a better made and more accurate remchester for the same or less money and get real service and parts back up to boot!

Other option- spend the same or less dollars on a good No4, treat it with care and use it well knowing you are not likely to wear it out and it will increase in value.
Another variation of this option- Buy two good No4's. Use one for many years in surplus rifle competition while the value of the other goes beyond what you spent on the two to start with. Your shooting rifle effectively becomes a freeby over time.

(NOTE# no metalurgists brains were sucked dry in the preparation of this posting)

Remember these- a real No4!

[Dimitri]

A Remington 700 receiver is heat treated, but I've not seen one that was "through hardened" or carburized.

Its got to be one or the other Tiriaq, but because of the lower carbon content of 4140 it does not get "through hardened" to the same Rc as you'd get a tool steel to.

There is no need to case hardened.

There is and there isn't, case hardening the outer surfaces of the receiver and bolt would allow the rifle to have a much higher life span, but wouldn't effect the operation of the rifle at the user level. However for Remington and many other rifle/action manufactures its a cost-benefit decision as the user of the rifle will probably never notice the difference in a bolt action hunting rifle.

So why should I heed the impotent bleating of self appointed "experts" who cast doubt on the reliability of an item that has not only been thoroughly proof tested, but has further stood the test of two World Wars?

One I am not a expert, just someone who went to college for Tool and Die (machining) and did the job long enough to know the properties of materials and know how to work within their limits. Two, to claim that the AIA rifle stood the test of 2 World Wars is plainly false. The No.1, the No.4 and No.5 all worked admirably well in 2 world wars, with the No.1 serving as a front line firearm in both, but the AIA other then a resemblance of the rifles, is not the same rifle.

Dimitri