On return, the loads were disassembled. They contain the right powder. They weighed loads are within 1/10 of a grain of the intended load. The bullet was a 180 grain BT by Nosler, and the diameter was less than .306 or .307. Accuracy even with the blown primers is excellent.
Anyone have any ideas what caused my problem? Ku-dude
quote:
Originally posted by ku-dude:
On my recent trip to RSA, I took reloads for my 30-338. These loads were carefully weighed, and assembled. It was a load that I had used without problem before, and which my gunsmith has used without incident for a long while. While warm, it is not a max load according to reloading books. After transport to South Africa in my checked luggage, about half the rounds fired blew their primers.On return, the loads were disassembled. They contain the right powder. They weighed loads are within 1/10 of a grain of the intended load. The bullet was a 180 grain BT by Nosler, and the diameter was less than .306 or .307. Accuracy even with the blown primers is excellent.
Anyone have any ideas what caused my problem? Ku-dude
You got a good one here. I don't really have any bright ideas, but I'd like to throw some fuel on the fire.
I'm not sure I buy the idea of the powder grinding down enough to do that in such a short period of time. The only well documented case of this that I recall was about 15 years ago when a Montana farmer touched off his 30-30 and it literally exploded. The factory box of 30-30's had been bouncing around in his glove compartment in the pick-up for a year! The powder has virtually turned to POWDER.
I'm also not sure about the temperature angle. I ran your load through a program and, assuming you're getting around 3,000 fps, a 35 degree increase in temp would equate to only about 4,000 psi. Not enough to blow a primer.
Two other possibilities come to mind. First (and very unlikely) is a batch of primers with thin or soft metal. The other is simply some debris in the barrel. During the days hunt it is possible for a bug to crawl in, or perhaps a small piece of vegetation from wherever.
Like I said, you got a good one here.
Steve
Regards
Ray Smith
Some people have had guns come apart with RE22 Lot#25083.
Regards
Ray Smith
I've had loads that were several grains under listed max blow out Federal 210 primers in a 25-06 and a 6mm Remington. Changing to CCI200 or WLR primers, all else the same, solved the problem. Thus, my suspicion would go to the primers unless you can definitely eliminate them as the source of the problem.
[This message has been edited by LE270 (edited 08-05-2001).]
WHO has had a gun come apart with Rel 22 lot....???
There have been reports of "higher than normal pressures", but none about guns coming apart.
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May I be half the man my dog thinks I am.
Not saying it "can't" happen, but sure don't have any answer.
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May I be half the man my dog thinks I am.
Two things to think about with respect to pressure (1) did any of your ammo lay exposed to the sun for any length of time. Ammo left in a vehiclcan overheat. (2) I read somewhere, I don't recall where, that the extreme cold experienced during the long flight to Africa could have an effect on some reloading components.
Just a side note.... I've always liked the idea that if you wanted a horse to work harder, you got a bigger stronger horse, you didn't try to over feed a little one to get more out of him. The moral of the story is if you need more velocity go to a bigger cartridge don't try to max out a smaller one.
I am working up the nerve to go fire some more of them, and see if it is a geography thing. Magnetic waves, coriolis effect, the Burmuda Triangle: give me a better explanation that it got bounced too much.
It has really got me scratching my head. Ku-dude
The first was that in repeated handling, the extruded powder granules broke down and altered the burn rate of that powder.
The second was that powder being hygroscopic, if loaded in conditions of high humidity that changes the burn rate.
The first option was duplicated my someone in that discussion, yet others using ammo stored in automotive glove boxes for months or years, never had the problem. Only way that could occur in a loaded cartridge is with significant jostling in a case with a low density of powder, certainly less than a compressed load. On the second option relating to humidity, if the charges weighed the same when broken down after the fact, that shouldn't have been a problem, but moisture will change the burn rate.
I know I didn't add much, but I too would like to know the answer.
Could the problem be your rifle instead of the loads? Could something have happened to or changed in the rifle as a result of the travel? Could something have changed, permitting the firing pin to travel farther, denting the primers more, or even piercing them? Could some permanent obstruction have somehow been put in the barrel? Is there any other change that could have occurred that would result in this problem?
Consider that whatever caused the problem may have occurred between the time the loads left your hand and the time you picked them up again at your destination.
1. What was the temperature and pressure in the baggage compartment of the airliner? Could either of those have been significantly lower than normal, and, if so, could that have changed either the powder or primers (either chemical or physical change) in such a way as to bring about your experienced result?
2. Is it possible that your baggage, containing the loads, may have been X-rayed, especially high-dosage X-rays, and, if so, could such irradiation have caused either a chemical or a physical change in either the powder or the primers? (I'm guessing that whatever changed, if indeed it was a change in the loads and not the rifle, was more likely to have been a chemical rather than a physical change because you say that when you pulled the bullets and looked at the powder it did not look different.)
3. As I wrote in a previous post, my suspicion still goes to the primers rather than the powder. If that is correct, detecting a chemical or physical change within the primer would be much more difficult than detecting a change in the powder. One way of testing this theory would be to pull the bullets on some of the loads in which the primers are blowing. Then discard the powder and bullets and replace them with exactly the same amount of new powder and new bullets from the same batches as those you pulled and/or discarded. Then fire those newly-loaded rounds. If you still get blown primers, this would be excellent evidence in support of the theory that the problem is in the primers.
[This message has been edited by LE270 (edited 08-05-2001).]
1. Take some of the powder from the defective loads and compare it under a microscope with a sample of the powder out of the canister from the same lot. If you can get access to one of those microscopes that allows side by side comparisons of two samples, so much the better. Such an examination might show some change in the powder that is not visible to the naked eye.
2. Pull the powder and bullets from several of the defective loads, then load that powder and those bullets in other cases with new primers from the same lot that you had loaded. The fire those loads to see whether you get the blown primers. If you do, this would give strong evidence to the claim that something happened to the powder to change it. If you do not get blown primers, then you do not have conclusive evidence, but it would tend to suggest that the primer was the problem.
3. Fire some of the defective loads in a different rifle in which other loads with exactly the same specifications have been fired successfully to see whether the problem occurs in that (second) rifle. If it does, this is conclusive evidence that the problem is the loads. If it doesn't, then you don't know for sure, but it may suggest that the problem is with your rifle.
4. How were your loads packaged? Is it possible that something in the packaging caused a chemical interaction with the powder or the primer compound, especially if the loads underwent very high or low temperatures, or low pressures?
[This message has been edited by LE270 (edited 08-06-2001).]
Perhaps a problem with the powder coating, due to past exposure to moisture? Heat might then have some nonreversable effect.
Interesting problem!
Without chemical analysis certainty will be impossible, but based upon your description I would place my money on the ammo being left out in the sun somewhere along the line. A high temperature excursion is the only likely phenomena that can permanently alter the powder's burn rate, and it always alters it towards the faster side.
H4831, even in it's various forms, is a stable and predictable powder. Vibration is very unlikely to do it. Africa has no monopoly on bumpy roads. Chemical decomposition is also unlikely. A change in the primer's detonation would at most change the pressure little more than the equivalent of 1 grain of powder, which is not sufficient to cause the pressures you describe.
Those bullets probably measured .3076"-3078". I think you need to calibrate your micrometer. I doubt Nosler is making .308 bullets that measure less than .3070"
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Warren Jensen
After dozens of flights, and countless thousands of miles bouncing around dirt tracks, I've never had anything like that happen to my ammo.
Consider sending a sample of the powder to the manufacturer with as much information as possible. Perhaps they'll analyze it and get back to you.
George
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Shoot straight, shoot often, but by all means, use enough gun!
Bullet drop is for me nowhere near as important as total confidence in my rifle and that total confidence comes IMHO from conservatism.