.375 H&H Case Head Separation-pics added

Slooshark1

Slooshark1

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I was shooting some test loads in my .375 H&H Ruger No.1 rifle today and I had one case that cracked right around about 3/16" in front of the belt and the case creased on the shoulder of the case about 5/8" long lengthwise on the case by about 3/16" wide x 1/8" deep. I had never seen this happen before. The primers looked okay so I don't think the pressure was too high. I had it happen with a second case where the case actually broke into two pieces and I had to run a boresnake through from the muzzle to try and get it out. The second case also creased on the shoulder, the same as the first one.

I have never seen this before in all my years of reloading and shooting. Does anyone have any idea what's going on? I didn't shoot anymore after that happened. I was shooting 78 grains of IMR4350 when the first one cracked and 80 grains of IMR4350 when the second one broke. I was looking at Steve's Reloading pages for 300 grain bullets and he recommended going as high as 81 grains.

.375Failureb.jpg

.375Failure.jpg

Please let me know if you have any insight to this.

Best regards,

Slooshark1
 
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I would bet money that the brass had been loaded and fired a number of times(perhaps with hot loads) and each time the brass had been full length re-sized. If I'm right, then the brass has been work hardened which caused it to fail.

When I had my 375 H&H, I always partially re-sized rather than full length re-sized.

Also, The IMR site lists 78 gr of IMR4350 as been max.
 
My guess is the same as Mauser98's.

If they were virgin brass, I'd be stumped.

<<edited to add>> If they have been reloaded several time, it's time to retire the whole batch.
 
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375 H&H cases are long and tapered. Liek many such cases, they are prone to seperation.

Also, some H&H chambers are GENEROUS...So FL sized cases get worked too much.

If the cases have been loaded 3 times, they are on their way to junk in a H&H..at least for full power loads.

If they haven't been loaded more than once, I'd say you are pver pressure.
 
If we were talking about a different class of cartridges I might agree that neck sizing is the solution, but to my way of thinking, function trumps all other considerations in a .375 H&H class rifle. If you only get a few reloads per case - that's just the cost of doing business, but if you have a neck sized cartridge that doesn't feed when it needs to, the cost could be much higher.

Therefore, my suggestion is that all .375 H&H ammo which is to be used in the hunting of large game be full length resized. I prefer to crimp if my bullet has a cannular, although some knowledgeable folks disagree with me on this, I believe it prevents bullets from being driven back into the cases and makes bullet pull weight more uniform. And finally all cases should be carefully inspected for signs of failure prior to loading.
 
Boomer said:
If we were talking about a different class of cartridges I might agree that neck sizing is the solution, but to my way of thinking, function trumps all other considerations in a .375 H&H class rifle.
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As long as it feeds and functions properly, what difference does it make what caliber it is?

I've neck sized only for several 375s (and a host of other bolt action calibers) with similar reliable results.

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SuperCub said:
As long as it feeds and functions properly, what difference does it make what caliber it is?

I've neck sized only for several 375s (and a host of other bolt action calibers) with similar reliable results.

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My point is that often these rifles are used on things that can bite back, and therfore I consider reliable feeding more important in this class of cartridge than with say the game that would be normally hunted with a .22 Hornet or a .243. I follow the same practice with all my big game cartridges, and only change my technique for my target and varmint guns

While my .375 is not an H&H, it is in the same class. This rifle is loaded 24-7, and the round in the bottom of the magazine may have many rounds fired over it before I get around to switching it out. When loaded with heavy bullets, the round left on the bottom of the magazine is battered inside the magazine box, and over time the shoulder expands slightly as the nose of the bullet is repeatedly driven into the front of the magazine box. Because I crimp, the bullet is not driven back into the neck, and because I full length resize even though the shoulder has expanded (slightly) the bottom rounds still chamber without effort.
 
to add to all the other coments, overpressure will never cause a simple case-head separation. If you are overpressure enough to make brass flow, something major will happen, like blown out primer pockets accompaniued by a frozen bolt, or major brass flow into ejector hole and into bolt face.

Case-head separation like you describe is simply from repeated firing with headspace on the large side. H&H belted cases of current manufacture are around 0.213" to 0.216". The saami gauges are 0.220" Go and 0.226 No-Go, so if you rely on the belt to headspace each time, you will stretch your case several thou each time.
 
rgv said:
Case-head separation like you describe is simply from repeated firing with headspace on the large side. H&H belted cases of current manufacture are around 0.213" to 0.216". The saami gauges are 0.220" Go and 0.226 No-Go, so if you rely on the belt to headspace each time, you will stretch your case several thou each time.
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This presents a good case for NEVER full length resizing a belted cartridge that will be fired in your rifle only. If one has problems chambering a neck sized round or with obtaining sufficient tension to hold the bullet under recoil his difficulies lie with his die set-up or rifle.
 
I think that everyone has pretty well nailed the cause of the split. And the options for preventing it in the future (eg use new brass OR neck resize) with pro''s and cons. The other possible cause of a case split which has happened to me involved a neck area (so was a different location) on a belted cartridge (350RM) that split because it was weakened by Sweets 7.62 that had been left in the chamber - very aggressive on copper.. and by extension .. brass
 
I htink the easy answer to FL vs Partial sizing for reliablity is to use partial sized brass for range work and use new or once fired brass for hunting purposes.

The chambe rin the H&H 602 I owned was generous, and I woudln't trust 2x fired brass in it not to seperate. Same for a 375 H&H I loaded for a friend, although his chamber wasnt too big...Afterr a coupel of case seperations on firing #2 and #3, you realize that you don't want to be mucking about wiht a seperated case when hunting...
 
OK. We know the separation was caused by excessive headspace due to excessive sizing. But, what about the crease on the shoulder?
The crease on the shoulder was caused by gas escaping from the separation split. This gas is then trapped between the case and chamber by expansion of the brass and, when the pressure inside the chamber is low enough, the brass collapses. This same sort of thing happens sometimes when loads developing too little pressure are used.
Work hardeneing of the brass is never the cause of a circumferential split. That is always caused by a headspace condition. Brass which fails from work hardening splits lengthwise. The exception to this occurs at the base of the neck where failure is occasionally circumferential or, at least, partially so. Regards, Bill.
 
Gatehouse said:
I htink the easy answer to FL vs Partial sizing for reliablity is to use partial sized brass for range work and use new or once fired brass for hunting purposes.

The chambe rin the H&H 602 I owned was generous, and I woudln't trust 2x fired brass in it not to seperate. Same for a 375 H&H I loaded for a friend, although his chamber wasnt too big...Afterr a coupel of case seperations on firing #2 and #3, you realize that you don't want to be mucking about wiht a seperated case when hunting...
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OUCH! I don't understand that at all. Certainly not suggesting that it's untrue, but I've shot more belted magnum cartridges through more rifles than I can count or remember, and have never had a head separation or case failure beyond a split neck. If even a split neck happened before 7 or 8 reloads I'd be looking for/expecting poor brass or some other problem. Even the old Imperial 300 H&H brass fireformed to 300 Wby. was reloadable at least 8 times.
Lately I've been playing with a P17 308 Norma mag. and using 300 Win mag. brass trimmed and sized down in Norma mag dies. This is the wrong way to go, as 300 H&H brass is a better way to do it. The shoulder of the Win mag brass looks like it was sized with a blunt cold chisel with some older cartridges, and will not form to a smooth shape with full power loads. However there still have been no case failures of any kind. Chambering and extraction is slick as a whistle after neck sizing only after the initial fireforming. If there had been a problem I'd have taken a long hard look at the rifle.
 
rodagra said:
OUCH! I don't understand that at all. Certainly not suggesting that it's untrue, but I've shot more belted magnum cartridges through more rifles than I can count or remember, and have never had a head separation or case failure beyond a split neck.
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Except in the case of the H&H, my experiences are similar- But I don't FL size most of them, just partial size. And they all have tight chambers, so no headspace issues. I size enough to reliably chamber. FL sizing of sloping cases like H&H and 303 British (especialy in generous chambers) seem to generate seperations faster, sharper shoulders don't.

After intitial fire forming, my H&H cases looked more like Weatherbys, :) so I mostly just sized 3/4 of the neck, to deal with the generous headspace. If I FL sized the bras 2-3 X, then it was almost certain to seperate. Similar with the other H&H, but i guess it's headspace was better, since we got a few more loads form it.

Generous chamber + FL sizing = seperation. Add in a tapered cartridge and you have quick seperation:)


If even a split neck happened before 7 or 8 reloads I'd be looking for/expecting poor brass or some other problem. Even the old Imperial 300 H&H brass fireformed to 300 Wby. was reloadable at least 8 times
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300WBy has a sharper shouldered case, and presumably a tight chamber.:)

Lately I've been playing with a P17 308 Norma mag. and using 300 Win mag. brass trimmed and sized down in Norma mag dies. This is the wrong way to go, as 300 H&H brass is a better way to do it. The shoulder of the Win mag brass looks like it was sized with a blunt cold chisel with some older cartridges, and will not form to a smooth shape with full power loads.
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Wouldn't necking down 338 WM brass be easier? Never tried it, just wondering...
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Leeper said:
OK. We know the separation was caused by excessive headspace due to excessive sizing. But, what about the crease on the shoulder?
The crease on the shoulder was caused by gas escaping from the separation split. This gas is then trapped between the case and chamber by expansion of the brass and, when the pressure inside the chamber is low enough, the brass collapses. This same sort of thing happens sometimes when loads developing too little pressure are used.
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Very interesting, I've not seen that before wiht the escaping gas.:)
 
Gatehouse, the "bible" suggests using 300 H&H, and I presume that's because you'd be sorta forming a new shoulder rather than trying to bump the existing shoulder back a couple of thou.
Regarding the crease in brass, usually just at or behind the shoulder; this can and does most often happen when using reduced loads with powders like H4831. Or so I've read.:) Based upon the opinions of a lot of pros I do not use reduced loads with any of the slow powders that are most efficient in large capacity cases. When fireforming brass in an unknown rifle with an "unknown" chamber I like to use a faster powder like H414 at maybe 1 or 2 grs. below max for the first few anyway. This gives me a hint what if any problems there may be before they can get too serious.
 
Necking down 338 to form 308 norma results in a case which is too short with a short neck after fireforming. I also use 300 Win mag brass to form 308 Norma because I prefer to use Winchester brass. Norma brass is and always has been, too soft. Regards, Bill.
 
How do I "neck size" a case? Do I just bring the handle on the ram down only enough to work the neck or do I require a special die?
 
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