Herter's .308 steel cased ammo failure (ruined my rifle)


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1KPerDay
May 30, 2011, 12:10 PM
You know all those guys who said not to buy or shoot this crap? The guys I ignored? They were right.:banghead:

First few shots through my Ishy Enfield. Some of the cases look fine, but (afterward) examining about half of them have primers backing out, and one, the last one in the magazine (luckily) ruptured. The shooter (my friend) got a face full of gas/particles but he was wearing eye protection and is fine. The rifle extracted normally (with noticeable more smoke throughout the action/magazine) and we examined the casing:

http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/73e6ec9f.jpg

http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/784f897f.jpg

The bolt will not close now. It seems to ME that the bolt head has been damaged in some way. The bolt rotates into position fine without the bolt head installed.

Anyone with an Ishy enfield, could you please take a close up pic of the gas relief port on the left rear of the barrel and post it up? Mine kinda looks like a figure 8 and I'm not sure if it did before or not.

I'm going to try to get my money back (or at least store credit) from Cabela's, as there's no WAY I'm running any more of this through my rifles. At least in .308. I've run several hundred TulAmmo .223 through my AR and Mini with zero issues. I wonder if they just didn't get the recipe right for .308.:confused:

IIRC it was about .50/rd or more when I bought it... I was desperate for some .308 and now it appears I've paid the price.:rolleyes:

More pics fyi... click for larger.

http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/th_a5e16a67.jpg (http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/a5e16a67.jpg)
http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/th_9aa46dd0.jpg (http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/9aa46dd0.jpg)
http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/th_f8ddf0f9.jpg (http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/f8ddf0f9.jpg)
http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/th_b0c24737.jpg (http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/b0c24737.jpg)
http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/th_e592349b.jpg (http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/e592349b.jpg)
http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/th_b357590c.jpg (http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/b357590c.jpg)
http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/th_4349ada5.jpg (http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/4349ada5.jpg)
http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/th_fa98f22e.jpg (http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/fa98f22e.jpg)
http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/th_5310e22b.jpg (http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/5310e22b.jpg)
http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/th_656b7f62.jpg (http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/656b7f62.jpg)

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GCBurner
May 30, 2011, 12:25 PM
Have you ever had the headspace checked?

TexasRifleman
May 30, 2011, 12:29 PM
Have you ever had the headspace checked?

Yep, that would be my first question as well before deciding it was just the ammo.

Ishapore Enfields especially are found with excessive headspace quite often. I would never fire an Ishy without knowing what the headspace was.

This ammo may have simply shown you something that was already there.

jungle
May 30, 2011, 01:03 PM
Just another opinion saying your rifle has all the signs of very excess headspace. The clues are the backed out primers and what appears to be stretch rings near the base of all the fired cases.

In the interest of your safety you should have the rifle checked for headspace prior to firing any other ammo of any kind.

Not to knock your rifle, but older Enfields have a long history of problems when chambered in 7.62 NATO. The Brits have said by official edict this can be a dangerous combination.
The Ishapores are newly built and not old Enfields, but the design is roughly the same.

1KPerDay
May 30, 2011, 01:06 PM
Thanks, I will. I suppose I'll have to have it repaired first, or the bolt head replaced (assuming that's the issue). Question: would headspace issues cause the case failure where pictured? I know that it can cause case head separation but I thought that occurred where the 'stretch rings' happen on the side of the case, not in the base.

1KPerDay
May 30, 2011, 01:29 PM
I browsed up this thread:
http://www.sksboards.com/smf/index.php?topic=19259.0;wap2

I don't have go/no-go gauges so I realize this info is probably not useful, but my bolt head measures .6325.

Anyone know a good enfield smith who may have proper-sized bolt heads available?

jungle
May 30, 2011, 01:31 PM
Normally you don't see a fracture like that, but it still points to a headspace problem, you may want to consider both rifle and ammunition suspect just to be on the safe side.

The bolt head can be perfect, but a long chamber will still lead to excess headspace. The only way to know is to measure it with a headspace gauge.
------------------------------------------------------------------------
The Indians were not the first to consider the Lee Enfield action (No. 1 Action) for use with the 7.62 NATO cartridge. In the 1950’s, both Britain and Australia produced experimental models in 7.62 NATO. However, they used standard steel, No 1 .303 actions to build the test rifles. The test rifles were not successful. Problems with bolt setback, fracturing and swift development of excessive tolerances spelled doom for these projects.



Source: The Lee-Enfield Story, Ian Skennerton, 1993, Greenhill Books

1KPerDay
May 30, 2011, 02:48 PM
Thanks. Mine is a 2A1 but as you know they are known for having generous headspace. They are also known for being very strong and made of good steel, but that doesn't help if headspace is bad.:banghead:

jungle
May 30, 2011, 03:00 PM
You may want to take a look at note 6 in this article.

http://www.surplusrifle.com/shooting2006/762ishy/index.asp

avs11054
May 30, 2011, 03:07 PM
Just an FYI...I have shot about 200 rounds of Herters from cabela's through my PTR 91. Not one problem yet. I don't know the first thing about enfields though.

1KPerDay
May 30, 2011, 06:57 PM
Yeah, jungle, I've read it. I've also read quite a bit of very passionate stuff here and elsewhere saying that .308 and 7.62 are identical for all intents and purposes.

And I imagine herter's is nowhere close to "hot" ammo. But I've been wrong before, as noted above. :)

TexasRifleman
May 30, 2011, 07:04 PM
I've also read quite a bit of very passionate stuff here and elsewhere saying that .308 and 7.62 are identical for all intents and purposes.

They have basically identical pressures but there are very big differences, especially noticed in rifles with headspace at or beyond the limits.

Nice thick NATO brass in your rifle might not show any problems simply because the brass is thick enough to hold up.

Where your cases are ruptured is exactly where NATO brass is thicker.

Maverick223
May 30, 2011, 07:06 PM
You may want to take a look at note 6 in this article.Note 6 is incorrect. There is virtually no difference in either pressure or external case dimensions (though NATO rounds do tend to have slightly less volume due to thicker brass) between 7.62NATO and .308Win. The difference is mostly due to the two different forms of measurement, not the measured values...unlike the .223Rem. & 5.56NATO. That said TR may be correct about the difference in brass thickness lessening the severity of the problem with NATO cartridges.

I concur that excessive headspace is the likely cuprit. The round that let go was probably just the weakest constructed and/or stoutest loaded of the bunch.

:)

Hizzie
May 30, 2011, 07:14 PM
Check headspace for sure to see if rifle caused ammo failure and not other way around. Thoroughly inspect action. See if a small piece of steel case is what is preventing action from closing.

TexasRifleman
May 30, 2011, 07:15 PM
That said TR may be correct about the difference in brass thickness lessening the severity of the problem with NATO cartridges.

Personally I think this is why many people believe .308 is higher pressure, because they shoot the thin walled commercial ammo in their rifle and it ruptures when NATO ammo doesn't. People want to blame the ammo in that case, but it's probably the rifle.

jungle
May 30, 2011, 07:32 PM
While there may be very little difference in the actual pressures of the two types of ammunition, the real difference, much like the 5.56 in tight .223 chambers, is in both the size of the chamber and in the blueprint allowable headspace.
There is a very real difference, whether this is going to effect your particular weapon depends on the exact chamber, headspace and ammunition. My preference is to play it safe and I use reloaded or factory ammo tailored to my weapons, I like my eyes and fingers and weapons in one piece. You can hardly ever go wrong running 40k psi in a weapon rated for 50K. :D

A better explanation of the REAL differences: http://www.303british.com/id36.html and http://www.303british.com/id69.html

Do a lot of weapons handle both rounds? Sure, but in this case, we have a good example of tolerance stack in the wrong direction.

Maverick223
May 30, 2011, 07:53 PM
While there may be very little difference in the actual pressures of the two types of ammunition, the real difference, much like the 5.56 in tight .223 chambers, is in both the size of the chamber and in the blueprint allowable headspace.The dimensions of the chamber is the same. Sure a 7.62NATO MG chamber has more clearance than your average .308Win. hunting rifle, but a 7.62NATO sniper rifle is tighter than the average hunting rifle. The same is true of commercial .308Win. chambers...some are tighter than others, it just depends upon the application and precision (a precision rifle will average a much tighter chamber than, say, a SA M1A).

:)

jungle
May 30, 2011, 07:59 PM
The dimensions MAY be the same, but they are not in the blueprints. The allowable headspace is quite different. NATO and SAAMI headspace guages are indeed different. A handbuilt sniper rifle may be different than NATO spec or SAAMI.

Manufacturers of reamers and headspace guages are well versed in the real differences, this is not an internet myth: http://www.forsterproducts.com/store.asp?pid=27204

The other interesting tidbit is that NATO does not use any steel cased smallarms ammunition, there is a good reason for this and it has a lot to do with case stretching in generous chambers. Brass is far more malleable and a better choice when using the same ammo in rifles and belt feds.

I find it very easy to distinguish rifle brass fired in true Nato chambers and SAAMI chambers when full length resizing. YMMV and some settlement may occur during shipping.

jonnyc
May 30, 2011, 10:41 PM
1K, check to see if there was any damage to your extractor.

SlamFire1
May 30, 2011, 10:49 PM
I don't see a headspace issue at all.

I see a flaw in the case head. The case head ruptured.

So what do people see that makes this a headspace issue?

Maverick223
May 30, 2011, 10:53 PM
The dimensions MAY be the same, but they are not in the blueprints. The allowable headspace is quite different. NATO and SAAMI headspace guages are indeed different. A handbuilt sniper rifle may be different than NATO spec or SAAMI.You are still comparing a .308Win. commercial bolt rifle to a MG...I sure hope there is a difference. :rolleyes: Compare a M14-EBR DMR to a commercial M1A and I'd be willing to bet they come real close.

So what do people see that makes this a headspace issue?C&R rifle + backed out primers = likely headspace problems (at the very least cause to check).

:)

jungle
May 30, 2011, 11:01 PM
There are going to be many variants, and for all we know the Indians may have their own non-NATO standard. The fact remains there are two different standards-SAAMI and NATO. We'll exclude European standards for the moment. Different rifles and manufacturers may stick to either standard or ream a compromise between the two based on the expected use of the weapon and anticipated ammunition. Blanket statements are difficult to prove true in any case. A commercial M1A is likely different than an issue M14, with good reason.

TexasRifleman
May 31, 2011, 12:09 AM
So what do people see that makes this a headspace issue?

Case head separation or rupture is exactly what you get with excessive headspace, it's the classic sign.

When a cartridge is fired, the thinner parts of the case expand, gripping the chamber walls. At the back, where the case is thicker, it can't expand easily so it stretches to the rear. Normally the bolt face limits that rearward movement. If the headspace is too long that rear movement will go beyond the limits of the case's ability to stretch, and it will rupture. And, since the base of the case is not in contact with the bolt, you get the primer pushed out then flattened since there is nothing back there to stop it initially, if at all.

Both of those signs are present in the OP's photographs so headspace would be something to check. And the fact that it's an Ishapore rifle, which are known to have headspace on the long end to begin with... I'd check headspace before anything else.

Now, all that said, the rifle may still have headspace that is within limits. Steel cased ammo doesn't stretch as well as brass, it tends to give out sooner. So, you take a rifle that has long headspace but right at the acceptable limits, add steel cased ammo that doesn't stretch and well, and you can get this here.

1KPerDay
May 31, 2011, 02:39 AM
Thanks again for all the great info guys... I can't tell you if headspace is indeed bad until I get the bolt issue figured out. I can't see anything around the bolt head nor in the rear of the barrel area that would prevent it but it's definitely a hard stop as the bolt head is trying to complete its final movement. It's weird, because it extracted fine. I'll try to take some pics and video tomorrow if I remember.

Not that I expect any of you to armchair-smith this thing, but I've learned a lot from you all in the past.

madcratebuilder
May 31, 2011, 08:47 AM
The dimensions MAY be the same, but they are not in the blueprints. The allowable headspace is quite different. NATO and SAAMI headspace guages are indeed different. A handbuilt sniper rifle may be different than NATO spec or SAAMI.

Manufacturers of reamers and headspace guages are well versed in the real differences, this is not an internet myth: http://www.forsterproducts.com/store.asp?pid=27204

The other interesting tidbit is that NATO does not use any steel cased smallarms ammunition, there is a good reason for this and it has a lot to do with case stretching in generous chambers. Brass is far more malleable and a better choice when using the same ammo in rifles and belt feds.

I find it very easy to distinguish rifle brass fired in true Nato chambers and SAAMI chambers when full length resizing. YMMV and some settlement may occur during shipping.

This.

Most rifles chambered in 7.62 NATO are head spaced to except both 7.62 and .308 (M1A, AR10). As parts wear and head spacing increases you can have a safe 7.62 but exceed head space for .308. having a field gauge for both 7.62 and .308 is a good investment.

1KPerDay, your rifle has a replaceable bolt head. These are made in different lengths to set the head space. That a look at the extractor to see if it's damaged, that may be the bolt closing issue.

SlamFire1
May 31, 2011, 10:00 PM
Case head separation or rupture is exactly what you get with excessive headspace, it's the classic sign.

When a cartridge is fired, the thinner parts of the case expand, gripping the chamber walls. At the back, where the case is thicker, it can't expand easily so it stretches to the rear. Normally the bolt face limits that rearward movement. If the headspace is too long that rear movement will go beyond the limits of the case's ability to stretch, and it will rupture. And, since the base of the case is not in contact with the bolt, you get the primer pushed out then flattened since there is nothing back there to stop it initially, if at all.

These are classic signs of case head separation. Stretching in the side wall. Cases are a lot thinner and weaker in the sidewalls.

The extractor groove has lots of brass. So why should the thickest, strongest part of the case break first, if headspace is the issue:confused:

http://img.photobucket.com/albums/v479/SlamFire/Reloading/300WSMCaseHeadSeparation1.jpg

http://img.photobucket.com/albums/v479/SlamFire/Reloading/300WSMCaseHeadSeparation2.jpg

http://img.photobucket.com/albums/v479/SlamFire/Reloading/300WSMCaseHeadSeparation4.jpg

FlyinBryan
May 31, 2011, 10:51 PM
yep. what slamfire said.

looks like defective case more than a headspace issue to me.

texas rifleman is correct that case heads will seperate with excessive h.s., but not where 1k's photos suggest.

jungle
May 31, 2011, 11:31 PM
I agree with the above two posts in that a head failure in the extraction groove is not normal, but how do you explain the backed out primers in the other cases and how do you account for the case heads movement out of square on the failed example-where did that head find room to move? If not in excess headspace, where?

A look at sectioned steel cases will show you more of a 90 degree corner at the base of the inner shell cavity. A section in this case might prove enlightening.

Whould you really continue to shoot this rifle without a headspace check?
Do you feel lucky?

Maverick223
June 1, 2011, 12:04 AM
[Would] you really continue to shoot this rifle without a headspace check?
Do you feel lucky?Exactly. If it were an autoloader it would be a more complex diagnosis...but this one is simple: Unless you can manage to make that bolt move mighty fast (I'm being facetious), the primers have nowhere to go in a properly headspaced manually operated rifle. Be it the only problem or not, headspace is almost certainly an issue (unless the cartridge case was improperly sized/formed and I highly doubt that). I'd be willing to bet that a thin washer could fit between a loaded cartridge and the breachface.

Time to check the headspace followed by an order for a bolt head a little larger.

:)

1KPerDay
June 1, 2011, 03:15 AM
I can't check headspace until the bolt head is fixed (or whatever's blocking it) as noted... so the question is moot. Based on what I've read I'm pretty confident the headspace will be (would be) close to max or above. However, I'm not convinced that the case failure was caused by excessive headspace. It seems to be in the wrong spot. But I guess it doesn't matter, as either way my rifle is out of commission.

That's a good idea about a cross section... I'll see if I can figure out how to do it without cutting my fingers off.

Jeff F
June 1, 2011, 10:56 AM
Well you have an Enfield that probably has a generous chamber to begin with, head space is probably on the long side but still in Mil Spec and your shooting steel cased ammo. Probably not a good combination. Steel is not going to stretch like brass. I shoot a couple of No4 Enfields in .303 and have had a number of case head separations but they have never done any damage. I'm curious as to what was damaged keep us updated.

TexasRifleman
June 1, 2011, 10:59 AM
The extractor groove has lots of brass. So why should the thickest, strongest part of the case break first, if headspace is the issue

Again, because we also have primers not flush with the pockets which indicates the brass was not contacting the bolt face when fired, only slammed back into it later. That means there was some extra room from something, and it's important to not ignore that and go straight to the case itself being a problem.

Remember also this is not brass ammo, this is steel cased ammo which does not stretch as well as brass.

If this was brass as in your picture, and no primer indications, we wouldn't be as suspicious of headspacing, but we have TWO indications of headspace, which means it's worth looking into.

As I said, it may not be excessive headspace alone but there is enough evidence to suggest it at least contributed to this and shooting a rifle with those indications might not be safe.

rikman
June 1, 2011, 11:15 PM
I'm a relatively new reloader and not a gunsmith...but based on your excellent pics and before I read others posts, I guessed excessive headspace as a most likely culprit. Glad you guys are ok.

Rikman

1KPerDay
June 2, 2011, 12:10 AM
http://www.gunpartscorp.com/catalog/Detail.aspx?pid=487530&catid=5830

according to numrich, the NO 1 MKIII, and NO 2A MKIII have the same bolt head... isn't the No 1 MKIII a .303? Can someone please confirm they use the same bolt head?

OhioChief
June 2, 2011, 12:51 AM
I'm not sure why you ask a great question, then not listen to the really great answers. Ya gotta head space problem! maybe other things, but that's your biggest one.

Maverick223
June 2, 2011, 02:51 AM
according to numrich, the NO 1 MKIII, and NO 2A MKIII have the same bolt head... isn't the No 1 MKIII a .303? Can someone please confirm they use the same bolt head?Not certain, but I believe the extractor is the only difference. The bolt head should be the same. However, you really need to find and fix the problem with your existing bits and get the rifle to function on some level (without firing) in order to determine which bolt head you need for proper headspacing as well as identify what the inherent problem is to compile an accurate parts list (could need more than just the bolt head, or perhaps no bolt head at all).

:)

SlamFire1
June 2, 2011, 11:29 AM
Again, because we also have primers not flush with the pockets which indicates the brass was not contacting the bolt face when fired, only slammed back into it later. That means there was some extra room from something, and it's important to not ignore that and go straight to the case itself being a problem.

Remember also this is not brass ammo, this is steel cased ammo which does not stretch as well as brass.

Could be an indication of low pressure. The primer backs out on ignition. Then if pressures are high enough, the case stretched back to the bolt face stuffing the primer back in the pocket.

If pressures are not high enough to stretch the case, the primer stays backed out.

Could there be excessive headspace, yes. But backed out primers are an indication of low pressures.

1KPerDay
June 2, 2011, 01:40 PM
I'm not sure why you ask a great question, then not listen to the really great answers. What makes you think I'm not listening? :confused:

Have you read my replies? I believe there is a headspace problem. I'm trying to get the rifle running so I can check it.

What am I missing here?

1KPerDay
June 2, 2011, 02:41 PM
Well I removed the extractor and the bolt closes perfectly. You smart folks that suggested it may have been the extractor... thank you. :cool:

I can't see any damage to either the extractor or the bolt head, other than some scorch marks... There is a noticeable "groove" in the rear of the barrel, in the extractor channel, that looks like the tip of the extractor is hitting and (I assume) getting hung up, rather than springing outward as it should.

I can't figure out why this would have changed due to a case failure; I suppose it may be coincidence.

I also assume that extractor ramp could be polished a bit to remove the 'step' caused by the nose of the extractor?

I also assume that it may feed properly with rounds in the mag, rather than closing the bolt without a case in place. But I haven't tried that yet.

I definitely will not fire this rifle again without it being checked for proper headspace (7.62X51) and I'm going to stick with lighter handloads and/or 7.62x51 BRASS ammo (assuming headspace is within specs).

Thanks to all, again, for your excellent feedback and advice. And let me know what you think about the extractor ramp, etc.

http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/th_3c53d15a.jpg (http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/3c53d15a.jpg)
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http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/th_5dc38249.jpg (http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/5dc38249.jpg)
http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/th_50f9e33f.jpg (http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/50f9e33f.jpg)
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http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/th_e0d0d236.jpg (http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/e0d0d236.jpg)
http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/th_cff0302f.jpg (http://i12.photobucket.com/albums/a206/1KPerDay/Guns/Herters%20steel%20cased%20ammo%20failure/cff0302f.jpg)
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buckfynn
June 4, 2011, 12:18 PM
I've also read quite a bit of very passionate stuff here and elsewhere saying that .308 and 7.62 are identical for all intents and purposes.

Nope, not true. Read the articles in the links below to see the differences between the NATO 7.62X51 and .308 Win.

7.62x51mm NATO or 308 Winchester? What's the Difference? (http://www.303british.com/id36.html)

And also.
.308 Win vs. 7.62x51--The Straight Scoop
Before we go much further, we want to address the oft-posed question "Are the .308 Winchester and 7.62x51 NATO one and the same?" The simple answer is no. There are differences in chamber specs and maximum pressures. The SAMMI/CIP maximum pressure for the .308 Win cartridge is 62,000 psi, while the 7.62x51 max is 50,000 psi. Also, the headspace is slightly different. The .308 Win "Go Gauge" is 1.630" vs. 1.635" for the 7.62x51. The .308's "No-Go" dimension is 1.634" vs. 1.6405" for a 7.62x51 "No Go" gauge.

http://www.6mmbr.com/308win.html (http://www.6mmbr.com/308win.html)

Maverick223
June 4, 2011, 12:31 PM
The SAMMI/CIP maximum pressure for the .308 Win cartridge is 62,000 psi, while the 7.62x51 max is 50,000 psi.That is just further proof that someone failed basic reading comprehension...NATO is measured in CUP (copper units of pressure) NOT PSI. The pressure (when put in the same units of measure) is near identical (as it was designed to be when Winchester asked to make a commercial copy of the 7.62NATO), the ONLY difference is the thickness of the brass. SAAMI says the two are completely interchangeable, but what do they know about sporting arms and ammunition? :rolleyes:

buckfynn
June 4, 2011, 12:41 PM
I was pointing out the difference in head space between the NATO 7.62X51 and the .308 Win which could very well cause the problems the OP encountered.

...the headspace is slightly different. The .308 Win "Go Gauge" is 1.630" vs. 1.635" for the 7.62x51. The .308's "No-Go" dimension is 1.634" vs. 1.6405" for a 7.62x51 "No Go" gauge.

1KPerDay
June 4, 2011, 01:13 PM
Yeah, but you also said this.

The SAMMI/CIP maximum pressure for the .308 Win cartridge is 62,000 psi, while the 7.62x51 max is 50,000 psi.

I personally think the case failure (where it occurred) was ammo related. However, I also think the evidence so far suggests the rifle has generous and/or excessive headspace, which MAY have somehow contributed to the case failure (hard to say exactly, but it can't help).

It was my fault for not checking the rifle for headspace beforehand. But I still feel the case shouldn't have failed where it did. In case the .308/7.62 issue is indeed an issue in this rifle, I'm going to avoid shooting factory-loaded .308 in it in the future. 7.62 is generally cheaper anyway, and I can always handload lighter loads.

Anyone know a good source for enfield bolt heads?

Maverick223
June 4, 2011, 05:04 PM
I was pointing out the difference in head space between the NATO 7.62X51 and the .308 Win which could very well cause the problems the OP encountered.They even misspelled SAAMI, that alone makes it a worthless source for gathering reliable information IMO. As far as the difference in chamber specifications, as I said before that changes in accordance to the firearm. A MG will have a very large clearance, a standard FA/SA autoloader will have a generous headspace, and a sporting bolt rifle/sniper rifle will have a tight headspace for precision. There is no clear-cut standard that every NATO/SAAMI chamber religiously follows.

Now back to the topic at hand...

1KPerDay, I think you are on the right track with reshaping the extractor groove (which was, in my unprofessional opinion, the result of escaping superheated gases cutting their way through the point of least resistance while exiting the breach), but it is a heck of a difficult place to get to with a dremel (or other similar grinding tool). Take it slow and easy and it will probably turn out okay. I, not having performed any work like this, am eager to hear how it does, but believe it to be at the very least safe (just wonder if it will work properly post-reshaping).

I personally think the case failure (where it occurred) was ammo related. However, I also think the evidence so far suggests the rifle has generous and/or excessive headspace, which MAY have somehow contributed to the case failure (hard to say exactly, but it can't help).Headspace is almost certainly an issue, but I suspect you are right about the case. That said, the case will likely rupture on the exposed/unsupported part of the case (which stretches too much; something easy to do with steel cases), despite the thicker brass (in your case malleable steel) in this area. If you would like, you can send me the case and I'll section it for you so you can see what was going on inside (PM me for details). Running a bent paper clip (to feel for grooves/malformation/anomaly) inside it might also tell you if there is a deformity in the case.

Anyone know a good source for enfield bolt heads?Try the guys mentioned in this handy list (http://www.surplusrifle.com/riflepartslist.asp).

:)

jungle
June 4, 2011, 07:37 PM
"Well I removed the extractor and the bolt closes perfectly. You smart folks that suggested it may have been the extractor... thank you.

I can't see any damage to either the extractor or the bolt head, other than some scorch marks... There is a noticeable "groove" in the rear of the barrel, in the extractor channel, that looks like the tip of the extractor is hitting and (I assume) getting hung up, rather than springing outward as it should.

I can't figure out why this would have changed due to a case failure; I suppose it may be coincidence.

I also assume that extractor ramp could be polished a bit to remove the 'step' caused by the nose of the extractor?

I also assume that it may feed properly with rounds in the mag, rather than closing the bolt without a case in place. But I haven't tried that yet.

I definitely will not fire this rifle again without it being checked for proper headspace (7.62X51) and I'm going to stick with lighter handloads and/or 7.62x51 BRASS ammo (assuming headspace is within specs).

Thanks to all, again, for your excellent feedback and advice. And let me know what you think about the extractor ramp, etc."
1KPerDay

Now that you have isolated the problem to the extractor you would do well to remember the axiom that one should always fit the cheapest part. Keep that dremel away from the extractor groove.

It is likely the gas changed the shape of the extractor in a way you can't detect, would it not be better to reshape the outer forward edge of the extractor until it fits? It looks as if the area to be altered is now clearly marked for you.
You may not need a new bolt head, headspace is best measured without the extractor in place.

The extractor on the 7.62 version is different than the .303, and you may end up having to alter a .303 extractor to fit in any event.

If the chamber is cut too deep, a bolt head won't fix it. People who did it for a living used a lathe to turn back the barrel breeching surface, a breeching washer and/or possible rechambering.

Go here and scroll down to the articles on breeching up and cartridge headspace. This gentleman knows his stuff and all of his articles are worth reading if you are an Enfield fan. http://www.milsurps.com/showthread.php?t=16948

1KPerDay
June 5, 2011, 04:16 AM
Thanks. The reason I was thinking of trying to polish the extractor groove is that I can see a visible "dent" there where the tip of the extractor is contacting it... but I suppose it's possible that it's just normal wear, and with an in-spec bolt head and extractor it may not be an issue. I cleaned and reassembled the bolt head today and it does the same thing... the pointed tip of the extractor seems to be contacting the rear of the barrel inward of the extractor groove.

As I suspected, it does chamber and close properly with a case in place (to hold the extractor away from the bore far enough to contact the ramp/groove properly).

You who have suggested the extractor may have changed shape due to gas contacting it have me thinking... I wonder if the escaping gas may have 'bent' it or heated it so the spring tension could push inward on the tip and reshape it or something... or perhaps the gas merely blew the cosmoline/crap out from the bolt head innards near the extractor, which allowed the extractor to move fully inward for the first time, where it may not have been able to before due to crud or something. I'd never disassembled the bolt head before.

In any case, thanks again for your excellent advice. I'll let you know what I find out if I can track down a set of headspace gauges.

Maverick, I may take you up on that offer to section the case (and maybe one of the others that didn't rupture but has obvious "stretch marks" and primer backing). :cool:

SaxonPig
June 5, 2011, 10:36 AM
Herter's went under 40+ years ago. How old is that ammo, anyway? Where was it manufactured? I associated steel cased ammo with China.

Jeff F
June 5, 2011, 10:54 AM
Herter's went under 40+ years ago. How old is that ammo, anyway? Where was it manufactured? I associated steel cased ammo with China.

Herter's is re boxed Wolf ammo made in Russia, anyways their .223 and 7.62x39 is. Cabela's sells a lot of it and I have shot a few thousand rounds of their .223 with no issues other then some rounds that had their primers set in sideways.

Maverick223
June 5, 2011, 11:21 AM
Maverick, I may take you up on that offer to section the case (and maybe one of the others that didn't rupture but has obvious "stretch marks" and primer backing).No problem, PM inbound...

:)

marinville
June 5, 2011, 02:15 PM
Herter's is re boxed Wolf ammo made in Russia, anyways their .223 and 7.62x39 is. Cabela's sells a lot of it and I have shot a few thousand rounds of their .223 with no issues other then some rounds that had their primers set in sideways.

Actually it's re-boxed Ulyanovsk, not Wolf.

Maverick223
June 5, 2011, 02:20 PM
Actually it's re-boxed Ulyanovsk, not Wolf.Uly. is now owned and operated by Wolf.

BTW, welcome to THR, marinville!

:)

marinville
June 5, 2011, 02:54 PM
Uly. is now owned and operated by Wolf.

BTW, welcome to THR, marinville!

I hadn't heard that. Are you sure you aren't thinking of Tula?

Thanks for the welcome.

helotaxi
June 5, 2011, 03:23 PM
Most rifles chambered in 7.62 NATO are head spaced to except both 7.62 and .308 (M1A, AR10).
I would add "US made" to the above statement. The typical problems that I have heard of usually involve foreign made rifles, not US made ones.

And the word is "accept." Sorry but that one just bugs me.

SeekHer
June 5, 2011, 03:37 PM
Not to knock your rifle, but older Enfields have a long history of problems when chambered in 7.62 NATO. The Brits have said by official edict this can be a dangerous combination.
The Ishapores are newly built and not old Enfields, but the design is roughly the same.

The British, Australians and Canadian all experimented with modifying the rifle to 7.62x51mm NATO and all with abysmal results.

Although with the headspace problem you have to remember that it doesn't apply to military rifles since they NEVER reloaded their spent cases.

The Ishapore is an Enfield in every aspect! The only thing different about them is they used a Cro Mag steel for the new receivers (to take the higher pressures), put a new barrel cut to 7.62mm but using the exact same barrel threading and of course replaced the bolt face with a different head to accept the rim (less) of the new cartridge...Otherwise all parts (except the .308 sight group), furniture, are identical and even interchangeable...They had the blueprints from Enfield and the right to produce them so they used the dimension set out in the original design with a metal change...Why change a good thing? Why have to retool to another rifle? Why have to change all the settings of the existing machinery?

The same thing with say a Winchester Model 94 rifle...The 1894 was originally chambered to fire 2 metallic black powder cartridges, the .32-40 Winchester and .38-55 Winchester. In 1895 Winchester went to a different steel composition for rifle manufacturing that could handle higher pressure rounds and offered the rifle in .25-35 Winchester and .30-30 Winchester and of course as metallurgy improved other calibres were added even to the .450 Marlin...In 1964, to save money on production costs, Winchester began machining certain small parts for the Model 94 (and all models as well) as opposed to forging them. The use of hollow roll-pins replaced solid ones...Just because the rifle, gets an improvement or is chambered in another calibre does not make it any less (or more) a Winchester Model 94.

It applies to any long running makers model even from post WW2 dates--Winchester Model 70, Remington 700 have all had metal changes over the years but are all still the same models...Remington even offered a Mauser (special run) version that had a different bolt face (CRF) but it still was a 700 in every other way.

Maverick223
June 5, 2011, 04:01 PM
I hadn't heard that. Are you sure you aren't thinking of Tula?Both Tula and Ulyanovsk are Wolf. For a while afterwards Uly was still producing ammunition to their specifications, but now I believe it is all built to Wolf specs. (definitely the case for newer Wolf Mil. Classic, which no longer uses the 8M3 "Sapsan" projectile). Tis a shame, because Uly was loading some nice ammo...at least when compared to Wolf/Tula (which isn't horrible when constrained to range/plinking, but not hasn't proven as accurate nor having as effective terminal performance).

:)

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