Some cartridges get the rap for pressure spikes or maybe it's blow ups. In any case is this really a fact or is it just rumor?

The link here is exploring this and the 7mm Rem Mag and 243 Win are up at the plate.

www.24hrcampfire.com forums, custom rifles and wildcats, interesting thread on the short mags.

I can only speak from personal experience...... I've seen more blown up (rendered unuseable) rifles in 243 than all other calibers combined.

I discount the obvious overloads, barrel obstructions, stupid tricks, and improper ammo wrecks that can be easily explained from that figure.

JBelk, could any of these blowups have been the mysterious and elusive "Secondary Explosion Effect"?

eldeguello---

I'm pretty sure three of them were. Several others were probably the result of thick necks or cases too long for the chamber.

The 243 *needs* a LOT of care in reloading. They can bite the careless VERY hard.

Jack,

Is this specific to the 243 or would you extrapolate it to the 244/6mm rem too?

Any views on what makes the 243 so sensitive? My own theory is that it's a higher pressure cartridge to start, the throat is generaly short so it's too easy to inadvertantly touch/jam the lands, the case is prone to stretching due to the long shallow angled shoulder and it's sensitive to fouling, throat erosion and temperature changes.

1894---

I've seen vastly overloaded 6mm Remingtons but never a failure that's not easily identifiable and attributable to something.

All you stated, and combinations of them, can cause problems and overpressure in the 243.

The 243 is a popular caliber but that doesn't explain why so many cause trouble and more common calibers don't.

Thanks Jack for the response.

At 24 hr campfire the thread that prompted me was by John Barsness (Mule Deer). He said that labratories report pressure spikes with the 7 mm RM and the 243 and cannot explain why.

I was unable to post the link. I may try again but it's worth looking at it there.

I guessed that deep seated bullets may contribute to it as Barsness said it only happened in the 243 with 100 gr bullets.

One of the worst wrecked pre-64 M-70s I've ever seen still had the 60 gr Sierra HP lodged in the barrel.

Don't ever think it only happens with big bullets.

I don't think bullets below the neck makes any difference at all. If so, there'd be no heavy bullets ever shot in a 300 Win. Mag.

For the sake of discussion, could the cause of the detonation be that the bullet moves into the lands at the primer ignition, and then stops, because the powder did not ignite completely, right off? Is that a plausible scenario? Dutch.

I have not done a detonation tests but Hodgdon has, and they have been unable to reproduce the phenomena with good rifles. They say that the 243 with a rough throat and a powder slower than IMR4895 and a half filled case may produce detonations.

Here is a picture of Lake City 308 brass necked down to 243 and not neck turned. All three rounds were 40 gr IMR4895 and 100 gr bullet. Closing the bolt took 100 pounds of force. This was in a 1903 Turk Mauser that I converted.


[ 03-21-2003, 20:45: Message edited by: Clark ]

Dutch--This has happehed in 6.5s and was written about in Handloader or Rifle Magazines.Discussed
in post below abou headspace.Ed.

Clark--

The study of the occasional detonation of slow powder was begun by Gen Hatcher at Springfield Arsenal in the 30s and continued at Aberdeen with the US Navy. HP White did an extensive set of controlled enviroment detonation experiments in the 60s and DuPont took it over in the 70s. Hogdens, Reliant, Norma and other component companies have tried, too........and ALL have failed, but NONE deny it happening!!!

There's a lesson in that.

I'd back off a grain on that far right one.

Thanks for the graphic depiction of the dangers of thick necks.

Who was the dummy that kept shooting them.?!

JBelk,
I am not ready to put detonation in the same category as global warming, second hand smoke health hazards, crop circles, UFOs, the Bermuda Triangle, or what load books and gun rags say about the strength of the CZ52.

I AM ready to put the danger of detonation with reduced H110 loads in straight wall cases in that same category.

I seem to post and post and it never sinks in, but that picture has been downloaded 3,000 times and seems to communicate. It may communicate I am a dummy to some, but to some it offers some reassurance about the 98 Mauser design.

There's lots of facts and speculation about blowups with light charges on this site. Apparently this was discovered as soon as smokeless powders were invented. Scroll down to the picture of the bottle with a fuse in it for one section, and further down to the gent with the blunderbuss for another section. Don't expect to get though it all in one evening.
http://guns.connect.fi/gow/gunwriters.html

Bye
Jack