I had posted this on another forum but thought the experience may be a useful reminder to check and double check your reloading practices.
http://www.jouster.com/forums/showthread.php?43897-Catastrophic-Failure
36g
I read a few pages of that thread.
I've had a similar incident, but with an M14 (Fed Ord).
Mine was caused by crappy brass. Primer was semi-auto safe (Winchester) and seated correctly. It was in battery, wasn't overloaded. The case head blew out. I wager yours was a case head blowout too, unless you had a slam fire from a high primer. There's a portion of the case that isn't supported by the chamber. Weak or brittle brass can fail there, and blow out.
The brass? Indian, OFV 87. I do NOT recommend reloading Indian.
Looks like I'll keep any Federal brass out of my M1, and use in in one of the Springfields or the Enfield instead.
And I got lucky. Needed a new bolt, new ejector and new stock. The mag was toast as well (3 rounds were in it and discharged).
Reading much further into the thread, and finally seeing pictures of the ruptured case, I'd agree with the high likelihood of this being caused by a failed case-head.
The question then becomes, what caused the case-head to fail?
Is it possible that the case was worn out?
The original poster of this KABOOM indicated that he reloaded once-fired Federal brass, using a full-length resizing operation. Whether the cases are *actually* once-fired, or twice-fired, or ten-times-fired is impossible to know; he indicated that he purchased them from a reputable merchant as part of a larger lot of mixed .30-06 brass. Whether once-fired or more, Federal brass is widely regarded as some of the softest brass to be found; it doesn't hold up well to 'hot' loads, and even normal loads tend to loosen the primer pocket in as few as 2-3 loadings.
There is another potential cause, brought up much deeper into the thread- the possibility of Bullseye pistol powder contaminating the powder dispenser, and thus dramatically changing the burn-rate of the H-4895 which was used.
Powder dispenser in question is the RCBS Chargemaster. Apparently, it is extremely difficult to fully clean out the 'guts' of this powder dispenser, and it has many nooks and crannies which can (and do) allow smaller-grained powders such as Bullseye to stick around. In testing this theory, the OP first completely disassembled and cleaned the machine, put in 1lb of Bullseye, had the machine dispense X number of charges at 20grs. He then 'drained' the assembly of powder, and used the 'trickle' feature to ensure that excess powder had been removed from the works. He then filled the chargemaster with H-4895, and upon close inspection, found bullseye kernels in the first charge of 46gr.
Lessons learned?
If you use a powder dispenser for both rifle and pistol powders, be absolutely certain that no cross-contamination takes place. The inconvenience of disassembling and cleaning your powder dispenser cannot come close to the inconvenience of finding all the pieces of your rifle while bleeding.
Use of commercial brass for loads that trend towards the hot side of a recipe is a potential recipe for disaster.
Quote from: Nickle on January 12, 2014, 07:40:48 PM
The brass? Indian, OFV 87. I do NOT recommend reloading Indian.
Yikes! I've got a bit of OFV 79, picked up after a match, once fired. The brass is noticeably different in color, even after cleaning and tumbling. Haven't loaded it yet, and I think after that story it's going into the scrap box.
Nero, don't scrap it, stick it a GI ammo can, and rat hole it. Check it from time to time to make sure it's dry and OK. If you ever need emergency ammo, it beats not having any. I've got over 600 rounds I'm doing just that with (had it when I had the incident). OFV 79 isn't the same as OFV 87, quality wise, from what I hear. But, why take a chance?
ItsanSKS, some good points there.
I', a very well experienced reloader. I ought to be, I've been a professional for it (as in got paid for it), and have been reloading most of my life, started before 10 years old.
#1 lesson I know is, NEVER buy or use an RCBS Chargemaster. I knew that before, and it's because they are as unreliable as the day is long. Similar systems seem to be better, or should I say "less bad", because NONE of them are even close to good. A very poor concept used by people that assume too much, and don't know what works. Tough words, I know, BUT I can back them up. I'll get a thread up on the whys of that, to help educate folks here, and take away that poor assumption, which by now is really a myth.
Federal brass is OK, just not in that usage. I think the real trouble here is "stack up" of little problems, creating a big one.
He was using a powder measuring system notorious for inaccuracy, and frequently dispensing too much powder. He was using brass well noted for being fine in a bolt action, but not so hot in a chamber that doesn't fully supported the case. He had previously had Bullseye in the powder dispenser, and may not have gotten it all out. He was using powder that has a steep curve, once over pressure (4895).
The other 2 cases didn't show signs of overly excessive pressure. So, it wasn't a real high concentration of Bullseye that got into the 4895. Not enough to make the other 2 over pressure.
The brass was obtained from a "reliable dealer". That's really an oxymoron folks, as a dealer that's big enough to be reliable, yet sells used brass is getting it from somewhere, usually range pickups. Who knows it has been used 1 or 20 times? I really trust exactly one brass to be once fired. Used military brass that still has the original crimped in primer in it. That's a safe assumption that it's probably really once fired. Then, I generally stick to known USGI brass, preferably Lake City (LC), Winchester (WCC) and Remington (RA). There's a few others that are OK, like PP (Prvi Partisan) and TZZ (Israeli).
I shoot Federal frequently in bolt guns. Perfectly OK. I usually just neck size those, in this application. The brass has lasted me over 100 reloads. Remember, that's specially cut tight necked match chambers, Wilson equipment, and a LOT of monitoring. Norma and Lapua brass are better anyways.
That case could have had a high primer, causing a slam fire, but I'm not so sure. The other 2 were OK.
So, like ItsanSKS, I also think case head failure.
Probably caused by a mild overload with weak brass in a rifle with a chamber that doesn't fully support the case head.