AIA #4 clone proofing

[harry mac]

What I am trying to get at is why is the strength of these actions being called into question? As far as I'm aware there hasn't been a case of one failing during use. Your point about metal fatigue is valid, but can be said of any object which is made from metal and has seen heavy or prolonged use.

[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.

[ireload2]

As far as the amount of flex in a Lee Enfield action is concerned, I suspect it is a lot more than a ten thousandth. Set up a rifle with minimum headspace, neck size to substantially reduce fireforming, and cases will still have a shorter lifespan than if used in a front locking rifle.
Cases stretch in a Remington 788 rifle because of bolt compression, not receiver flex.
But rear locking actions do have characteristics not observed in front locking ones.
A Remington 700 receiver is heat treated, but I've not seen one that was "through hardened" or carburized. They can be drilled or machined without difficulty - for sight mounting holes, blueprinting, etc.
The AIA rifles obviously withstand industry standard or proofhouse testing. Prooftesting does not mean that a firearm will not fail at a later date.
Many owners report them to be perfectly satisfactory rifles.
Everyone's cup of tea? Obviously not. Certainly the product of a rather atypical company. Long term future? Who knows?

The M700 receiver is through hardened it is just not extremely hard and does not need to be. 1898/09 Argentine Mausers that are so popular for building custom rifle are usually about Rockwell B80 (~C0 that is Rockwell C Zero)
and are too soft for hard use with a lot of high pressure cartridges. later M98 receivers are often carburized to C32 to about .010 deep. The M700 is about C44 all the way through. It is much tougher than ANY Mauser 98 except maybe a cast Mauser clone that is cast from 4140.

The following are my results for the bolt compression and receiver stretch for a #4 Lee Enfield action.

..............................Receiver.......Bolt. .............Total Deflection
..PSI.........................Stretch......Compres sion....Receiver+Bolt
30000........................0.0009.......0.0037.. ........0.0046
35000........................0.0011.......0.0043.. ........0.0054
40000........................0.0013.......0.0049.. ........0.0062
41440........................0.0013.......0.0051.. ........0.0064
45000........................0.0014.......0.0055.. ........0.0069
50000........................0.0016.......0.0061.. ........0.0077
55000........................0.0017.......0.0068.. ........0.0085
60000........................0.0019.......0.0074.. ........0.0093
65000........................0.0020.......0.0080.. ........0.0100
70000........................0.0022.......0.0086.. ........0.0108
75000........................0.0024.......0.0092.. ........0.0116
80000........................0.0025.......0.0098.. ........0.0124
85000........................0.0027.......0.0104.. ........0.0131
90000........................0.0028.......0.0111.. ........0.0139
95000........................0.0030.......0.0117.. ........0.0147
100000...................... 0.0032.......0.0123..........0.0154
105000...................... 0.0033.......0.0129..........0.0162
110000...................... 0.0035.......0.0135..........0.0170
115000...................... 0.0036.......0.0141..........0.0178
120000...................... 0.0038.......0.0147..........0.0185

[Alfred]

As far as the amount of flex in a Lee Enfield action is concerned, I suspect it is a lot more than a ten thousandth. Set up a rifle with minimum headspace, neck size to substantially reduce fireforming, and cases will still have a shorter lifespan than if used in a front locking rifle.
Cases stretch in a Remington 788 rifle because of bolt compression, not receiver flex.
But rear locking actions do have characteristics not observed in front locking ones.
A Remington 700 receiver is heat treated, but I've not seen one that was "through hardened" or carburized. They can be drilled or machined without difficulty - for sight mounting holes, blueprinting, etc.
The AIA rifles obviously withstand industry standard or proofhouse testing. Prooftesting does not mean that a firearm will not fail at a later date.
Many owners report them to be perfectly satisfactory rifles.
Everyone's cup of tea? Obviously not. Certainly the product of a rather atypical company. Long term future? Who knows?

My No.4 is fitted with a no. 3 bolt head and new condition bolt body, and I set the lugs and seats nicely with an accidental overload early on in my handloading for this rifle.
I'd substituted a pulled Mk VII 174 gr bullet for a 150 grain bullet with the fairly modest charge I normally use for the 150 , which should have been no more than a safe max load for a 180 grain. Whatever the reason that load swelled the primer pocket and near erased the headstamp. I'm much more careful now, and there was no damage to the rifle.
Group size shrank to half that of groups fired before setting the lugs in their seats.
Head gap with a S&B case with rim of .063 was less than .004, gap is of course several thousandths more when thin rim commercial cases are used, but I never again lost a case to stretching or cracking.
My loads for the no.4 run at 46,000 to 48,000 PSI, near max by SAAMI standards.
I neck size only, and to insure ease in loading in the field I use each fired case as a snap cap for dry firing practice, this sort of micro sizes the case body to the chamber.

I rotate each case 180 degrees at second firing, this eliminates any unequal swelling of the case body, from second firing onward each case is a perfectly centered fit to the chamber.

I figure that in part the shorter case life some experiance despite relatively tight headspace is due to several factors working together. Centering the case body to the chamber leaves little leeway for these factors to overwork the case.

I once owned a 788, not a bad rifle but too generic for me at the time.
From what was known of the action then case life problems were put down to the inability to get a good even bearing of its rows of multiple lugs.
Those who used this action in competition prefer to lap the lugs for even bearing, and this seems to do the trick for them.
Normally a three lugged bolt acts like a tripod and even bearing is natural, but when there are rows of three lugs only three lugs will bear naturally, the rest will not bear until pressure sets the three bearing lugs back, this results in springing of the three bearing lugs till they wear into place or are set back in the seats. Lapping the lugs hastens the wearing in process.

Three substantial lugs will perform better than multiple rows of three lugs with less meat to each lug.

[villiers]

That is where your wrong, a proof load can be passed with a rifle of questionable manufacture that would not hold up after repeated firings.

Its like a weight lifter, a weight lifter can max out with 500 pounds and do it a couple of times without showing signs of not being able to, just as a rifle can handle a couple of proof loads, but when that same weight lifter does sets, he may only be able to do 250 pounds 15 times before having to stop.

Metal fatigue is the issue, not necessarily the rifle passing the proof testing. Especially when materials of questionable origin are used. Most military and commercial arms continue to use the same few materials as they always have because the arms designers know they work and will hold up in the long term with little to no metal fatigue from repeated firings, as well as can handle the pressures generated with proof loads.

Dimitri

When this topic was previously discussed and I pointed out that my rifle had been proofed in the UK AND in Germany, I `phoned the Federal German proofing authority and was assured that proofing standards in the EU are NOT limited to proof firing the weapon. The action is removed from the stock and inspected for material damage, headspace is checked and the weapon inspected thoroughly. Proof houses in Germany and the UK have been doing their job for hundreds of years. They are government agengies and would be liable for any damage caused by their negligence.

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?

[Alfred]

When this topic was previously discussed and I pointed out that my rifle had been proofed in the UK AND in Germany, I `phoned the Federal German proofing authority and was assured that proofing standards in the EU are NOT limited to proof firing the weapon. The action is removed from the stock and inspected for material damage, headspace is checked and the weapon inspected thoroughly. Proof houses in Germany and the UK have been doing their job for hundreds of years. They are government agengies and would be liable for any damage caused by their negligence.

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?

I think you're conflating the previous discussion of WW2 era No.4 actions in 7.62 NATO with this No.4 styled but not actually No.4 or Enfield M10 action and its differing metalurgy and manufacturing techniques.

The basic Lee design elements remain, but this is not a No.4 any more than a No.4 is a Lee Metford.

A rear locking action is more subject to metal fatigue if for no other reason than much more of the receiver's structure is subjected to stress under pressure.
The receiver ring is highly unlikely to fail, because unlike front locking actions the receiver ring serves only to secure the barrel to the rails of the receiver.

The only real question as far as the M10 is concerned is how durable the alloy used in its construction is to repeated stress of firing the more intense .308 loadings or the highest pressure 7.62 loadings such as M118 Long Range Special Ball.

Proof testing eliminates the defective rifles, but doesn't predict the effect of continued use, and can't forsee abnormal conditions that a rifle might be subjected to. An example of such abnormal conditions came up on a long range brench rest forum recently. Ammunition loaded to maximum safe pressures where temperatures hovered around 60 degrees proved to be a dangerous overload when the shooter went to a match where temperatures approached 90 degrees.
A reported failure of a No.4 rifle using a European MkVIIIZ type ammunition suggested that the ammo had been developed for use in low temperatures and higher ambient temperatures resulted in excessive pressures.
A quoted reference to extra hot loaded MkVIIIZ ammunition in use in a desert environment told of extreme high pressures with the primers so flattened as to looked "painted on".

My opinion on the converted No.4 rifles proofed to the 19 T mark is that they should be safe enough with ammunition that generates pressures no higher than standard Ball Ammo, around 48,000 CUP which is equivalent to MkVIIIZ.

The question of whether the M10 action is strong enough for extended use of higher pressure loads like the M118 LRSB or the hottest commercial .308 ammunition will be answered with time and use by owners of these rifles.


As for casting doubt on the reliability of the Lee Enfield type action, no action type has a perfect safety record, The Ross debates provided numerous examples of LE action failures, and the warnings that SMLE action bodies can crack if a wet cartridge is fired indicate that theres always been concerns about the safety margin of the SMLE at least. The No.4 receiver and metalurgy are stronger than that of the No.1 in most cases, but the bolt itself is marginally stronger at best.


A rifle can last for generations if not abused by loads that exceed its design limitations. No sense letting emotional attachment or pride over ride common sense in chosing the best ammunition.

I wouldn't subject a 1893 Mauser to the highest pressure 7MM ammunition available today, I wouldn't subject a high number Springfield to the hottest possible .30/06 loads either.

[ireload2]

>>>They are government agengies and would be liable for any damage caused by their negligence.<<<

Just because the agency has fulfilled the requirement to proof a rifle does not mean they have any further liability. All they do is prove the rifle is not an immediate threat for catastrophic failure.
There is one case that I know of where the proof house struck the proof mark and cracked the receiver of an expensive rifle. The manufacturer had to pay for the replacement receiver. The damage was never noticed by the proof house or by the manufacturer. The odd thing is the rifle design was one which has the locking shoulders in the barrel extension. The receiver does not bear any load from firing. Yet the proof house had to stamp the receiver and they stamped it near the edge cracking it.

[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