The "Dangerous Eaton Carcano" - A Myth Busted - Updated 2 June

[Andy]

Andy
What kind of markings did the cooey/eaton/carc have?I have one in very poor shape w/double triggers/sleeved barrel shank and absolutely no markings.
Also when the Italians did a Tubatto (sp) was it a regular reline as it is done today or a shank insert as cooey did them?
Rich

My Cooey Carcanos have no markings aside from what you see in the pic, and "6.5mm" - no Eaton, Cooey, nothing else.

I have an Italian Vetterli 1870/87/15 (also "dangerous to shoot", but in this case it's true if you exceed Black Powder pressures, i.e. about 20K). It is sleeved in the "usual" way - original 10.4mm barrel bored out with 6.5mm "sleeve" inserted. Shoots pretty well.

The "stub" method is not that unusual so I am told (some SKS's use it), and apparently works well.

 

[Lee Enfield]

It is the same gun - but you knew I was going to abuse it.

On the bright side, Clean out the chamber, replace the extractor and it would be good to go. However I am going to remove the barrel, and determone once and for all how the barrel was affixed to the stub - pressed in with a set-screw? Threaded in with set-screw?

NOTE:( I initially miss-read your post to indicate that you intended to put the gun back together & shoot it like nothing unusual had happened, even so this probably needs to be said because someone might emulate your testing )

Once you have overstressed the(any) action to the tune of 100,000 psi IT SHOULD NOT EVER BE USED AGAIN FOR SHOOTING. If you are planning more remote testing go ahead, but NEVER EVER let that action out for shooting by anyone else.

When you pull the barrel, I'm very interested to learn whether there is any deformation under the sleeve.

The action & bolt were designed & built at a point in time with limited metalurgical advancement & all heat treatment was done by EYE.

Just because we cannot see any damage doesn't mean that it is not there.

Magnaflux/mag-particle and X-ray may not show all of the damage.

At the very least your action may not have experienced visible set-back, but the bolt lugs may have experienced significant deformation. For sure there was significant temporary deformation.

I have seen a (Czech 98/24 IIRC) M.98 mauser bolt which lost it's lugs upon firing. It was not a pretty experience. The 3rd lug only slowed it down.

Regards
D

 

[Andy]

Once you have overstressed the action to the tune of 100,000 psi IT SHOULD NOT EVER BE USED AGAIN FOR SHOOTING. If you are planning more remote testing go ahead, but NEVER EVER let that action out for shooting by anyone else.

Agree. I was careless not to make the same point, and more careless to suggest that I might do the opposite. Both actions have been "retired". Just because the firearm survives a high-pressure firing without apparent damage does not mean that no damage has been done, or that it could consume a steady diet of the same pressure. One can surmise though, that if it survives 100K psi even once, that it could safely handle 60K psi ad nauseum, which was the point of the whole exercise.

 

[david doyle]

Nice work ANDY. It is refreshing to see someone actually doing something more interesting with rifles then adding a leopould scope to a remington 700.LOL

Let us see the barrel when you get it peeled off.

Cheers
D

 

[RR]

Andy
Talked to a buddy in Alberta this morning he said he knows of 2 C\E\Carcanos with pistol grips and double triggers both chambered in 6.5 carcano.If you fired 6.5 manlicher in the carcano chamber I bet it would make a mess.
Rich

 

[desporterizer]

You would have to hammer the bolt shut, ms is 2mm longer. I did try it btw, just to see if it was possible( chamber a round, not fire the gun).

 

[Andy]

Andy
Talked to a buddy in Alberta this morning he said he knows of 2 C\E\Carcanos with pistol grips and double triggers both chambered in 6.5 carcano.If you fired 6.5 manlicher in the carcano chamber I bet it would make a mess.
Rich

Rich,

To the best of my knowledge, the Eaton Carcanos were all chambered in 6.5 MS which is very close in all dimensions to the 6.5 Carcano (6.5x52), but a bit longer. A 6.5 MS should not chamber in a 6.5 Carcano chamber, but the reverse can be done. In fact until recently most 6.5 Carcano ammo was made from 6.5 MS brass which was much more common, and easily sized down.

Firing a 6.5 Carcano round in a 6.5 MS chamber would be uneventful - it would just fireform.

 

[Claven2]

Rich,

To the best of my knowledge, the Eaton Carcanos were all chambered in 6.5 MS which is very close in all dimensions to the 6.5 Carcano (6.5x52), but a bit longer. A 6.5 MS should not chamber in a 6.5 Carcano chamber, but the reverse can be done. In fact until recently most 6.5 Carcano ammo was made from 6.5 MS brass which was much more common, and easily sized down.

Firing a 6.5 Carcano round in a 6.5 MS chamber would be uneventful - it would just fireform.

Not necessarily. Sometimes firing undersized ammo can cause its own set of safety problems, though it's much less likely than with over-charges.

 

[RR]

When I was measuring carcano against 6.5x54 I really goofed.I just pulled a supposed 6.5x 54 out of a bag and measured it.I couldn't read the headstamp.After reading your post I looked up the cartrige dimentions,got the calipers out and got into the bag of 6.5 x54, what a mix.6mm usn, 6.5 dutch,
6.5x54 and 3 more that I have no idea. No wonder I had the dimentions wrong.
Rich

 

[Lee Enfield]

One can surmise though, that if it survives 100K psi even once, that it could safely handle 60K psi ad nauseum, which was the point of the whole exercise.

60K psi is well above the pressure of the original cartridge (40K psi range IIRC).

The action design may be perfectly comfortable at 60K, but there are other considerations.

~metalurgy & inclusions
~heat treatment
~work hardening
~metal crystalization
~previous damage
plus then there are added complications more specific to the barrel
~craze cracking
~corrosion

Unfortunately being as we have no idea what the previous history of any given firearm is, so we need to stick much closer to the original design parameters than 20K of extra pressure.

As they say in the reloading manuals "... loads herein were found to be safe in the authors rifle...." "....each gun is a law unto itself...."

Regards
D

 

[Gibbs505]

Better, in this case, to be safe the sorry!!

 

[MiG25]

very interesting.

brings to mind the question as to why P14 enfields are considered suitable for rework into belted magnums, while the 93/95/96 mausers are not considered safe for anything generating higher pressure than the 300 savage. i can't comment on metallurgy, but swedish steel was famous and the 96 style action was made well after the last P14. granted spanish steel has a bad rap (another myth???), but the germans knew as well as anyone how to make a rifle.

i'd submit my bubba'ed oveido made in 1909 for testing, except that it is VERY accurate.

 

[Lee Enfield]

very interesting.

brings to mind the question as to why P14 enfields are considered suitable for rework into belted magnums, while the 93/95/96 mausers are not considered safe for anything generating higher pressure than the 300 savage. i can't comment on metallurgy, but swedish steel was famous and the 96 style action was made well after the last P14. granted spanish steel has a bad rap (another myth???), but the germans knew as well as anyone how to make a rifle.

i'd submit my bubba'ed oveido made in 1909 for testing, except that it is VERY accurate.

Well I had a great reply, but I timed out & lost it

Anyway to recap much shorter:

The Swedish mauser is constructed of a (swedish produced) Nickle-Steel Alloy. This includes the early Mauser produced ones. According to the book Crown Jewels by Dana Jones all of the Swedes were constructed from the same nickle steel alloy from 1894-1944 (M.94/96/38).

Swedes were built/rebuilt for commercial sale in .30-06 by Husquevarna. It's actually more a matter of size of the action, barrel shank & availability than any inherent weakness that explains why they were not used as magnum sporters.

While we see a lot of them today they were quite uncommon 40-50 years ago.

Belgian/Spanish/Chilean/ZAR m.89-97 mausers were not mfg of Nickle-Steel Alloy.

P-14s were produced by commercial American gunmakers of Nickle-Steel Alloy right from day 1, they were then also heat treated in a modern fashion.

(here is a good link which touches on the metalurgy & heat treatment of the day by an ordnance engineer: http://www.odcmp.com/Forms/M1917.pdf )

The P-14 series action is also hugely overbuilt for .303Brit & .30-06. This is because it was DESIGNED around a cartridge inspired by (& based on) the .280 Ross cartridge which is roughly comparable to todays 7mm Remington Magnum.

Comparable military actions such as the Ross, Springfield & m.98 Mauser were case hardened/carburized by eye.

Lee Enfield MkIIIs were common mild ordinance steel (with a bolt mfg of better grade steel)per Skennerton.

 

[tiriaq]

Just an observation about the Swedes - having drilled and tapped 96s and 38s, the 96s give every indication that they are surface hardened, while the 38s are not. May be the same steel, but the heat treatment is not the same.

 

[Rapt]

One can surmise though, that if it survives 100K psi even once, that it could safely handle 60K psi ad nauseum, which was the point of the whole exercise.

Best not to surmise.... Do some research on metal fatigue. As an engineer you should be able to handle the techincal aspects.

Just because it can handle 100k psi doesn't mean it can handle any given pressure infinitely... Shape factors etc all play a part.

And as one of the other posters pointed out heat treating was a bit hit or miss back then and you could get "unlucky" as easily as lucky with the strength of other examples. Is it really worth finding out the hard way?

 

[Andy]

To my amusement this exercise has been for nought, its critics bringing it back to point 1 - that the Carcano action is not to be used above its "original design pressures" (which is assumed to be that of the 6.5x52 Carcano), and that the Eaton Carcano action is "inherently weak".

While I do not agree with some statements, I see no point in raising any objections, so essentially I have nothing more to offer on this subject and am signing off this thread.

I will continue to post on whatever else I find about the Eaton Carcano - for example, just how the barrel stub is affixed (it goes to the gunsmith this afternoon).

You other guys - read lots and follow it to the letter, stick to the load manuals, and always check headspace, as poor headspace kills.

 

[tiriaq]

Rising to Andy's bait..... Just to muddy the headspace water - everyone is probably aware of who Bob Greenleaf is - when Bob was still at Savage he decided he wanted to experiment with excess headpace. Used a 110, of course, and prceeded to unscrew the barrel, firing along the way until the barrel was screwed out so far it became ridiculous. Now, this was done under controlled conditions, using new factory ammunition, with no consideration of ever reloading the brass. As long as the extractor gripped the case, the cartridge would fire. Nothing untoward ever happened, no separations, no KB, nothing. The cases fireformed, of course. With a design that poorly supports the casehead, and with brittle brass, things might be different.....

 

[spi]

I will continue to post on whatever else I find about the Eaton Carcano - for example, just how the barrel stub is affixed (it goes to the gunsmith this afternoon).

$100 says that it is threaded in and the set-screw is just there as insurance against rotating. I say this because of the alignment notches on reciver and barrel (chamber?) sleeve.

 

[Lee Enfield]

To my amusement this exercise has been for nought, its critics bringing it back to point 1 - that the Carcano action is not to be used above its "original design pressures" (which is assumed to be that of the 6.5x52 Carcano), and that the Eaton Carcano action is "inherently weak".

While I do not agree with some statements, I see no point in raising any objections, so essentially I have nothing more to offer on this subject and am signing off this thread.

I will continue to post on whatever else I find about the Eaton Carcano - for example, just how the barrel stub is affixed (it goes to the gunsmith this afternoon).

You other guys - read lots and follow it to the letter, stick to the load manuals, and always check headspace, as poor headspace kills.

Wrong, I totally agree with you. The Carcano is NOT a weak design by any means. For an action put into production in 1891 it was superior or equal to any of the competing designs (Steyr, Berthier, Lee Metford, Moisin-Nagant, Krag, M.89-93 Mauser, pre-95 Mannlicher straight pulls).

Carcano's were PRODUCED in 8mm Mauser during WW2 & survived quite well. Krags were also produced in 8mm Mauser during the Nazi occupation & again did quite well.

My POINT is that ANY cartridge chambered in ANY action should be within the original design parameters.

My reasoning is that if you were to take that original 1891 produced Carcano (or Krag) & rechamber it from 6.5 to 8mm Mauser/.308 win ect. you are just asking for trouble. While it could hold together for thousands of shots, it may CATASTROPHICLY FAIL! at the first one.

 

[tiriaq]

Does this not assume that a given design was intended to be adequate for only for the single specific original cartridge and load? Consider the 98 Mauser for example, because it is probably among the most widely distributed and most extensively modified and used military action. The action was designed to be made using modest low carbon steel, surface hardened. Its original cartridge was moderately loaded, with a bullet that achieved modest velocity. It has been converted to just about every cartridge that could fit the diameter and length parameters of the action, with little consideration for either pressure or backthrust. Unfortunate occurences are extremely rare. Is it possible to say what the intended design limits were for any given action? We know from empirical evidence the SMLE is at its design limit with 7.62x51, even if steel specifications are enhanced and proof testing is less rigorous.
Consider the DC-3/C-47 airframe: When it was designed in the mid 1930s, were any of the engineers aware that their airframe essentially did not have a service lifespan, barring mechanical damage or corrosion?
It certainly does no harm to stay within the limits of cartridges originally used in a given design, but if this were an absolute, there would be no Mauser sporters chambered for rounds excceding the pressures and backthrust generated by the 7.92x57I cartridge - about the equivalent of .303 and .30-40 Krag. How many modern sporting cartridges operate at pressure levels this low?