Forums
New posts
Search forums
What's new
Articles
Latest reviews
Author list
Classifieds
Log in
Register
What's new
Search
Search
Search titles and first posts only
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Bullets vaporizing in mid-air
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="Kevin Thomas" data-source="post: 288812" data-attributes="member: 15748"><p>Howdy Tye,</p><p> </p><p>Not exactly unheard of, and not too uncommon in some combinations. Berger had some problems with this some time back and have since modified their line to eliminate such problems. You've already touched on part of the answer here; heat. Eric Stecker of Berger Bullets did some very extenisive testing with MIT and high-speed thermal images of bullets in flight to determine what was causing this phenomenon. They took a serious look at the causes here, and spent the time, effort and money to do it right. It comes down to heat, migrating through the jacket and melting the core, or at least a boundary layer of it under the jacket. Once the core goes plastic or liquid, any void in the jacket will allow it to outgas, and the bullet blows. By reviewing the thermal images, Eric was able to discern the actual temperatures of various areas of the bullet in flight, and it's not what you'd automatically expect. The base, for example, stayed quite cool despite being in contact with the hot powder gases. The ogive (not surprisingly) didn't heat up too badly. The real hot spots were the meplat, due to the friction of the air and nose pressure. The worst, though, was the bearing surface, particularly where the rifling was engraved upon firing. This portion hit several hundred degrees, almost instantly. The analysis concluded that the jackets were thin enough to allow the heat to penetrate to the core, and bad things happened. To resolve this, they thickened the jackets to allow for better "insulation" of the core, and the problem now seems to be entirely resolved. Just look for the bullets that they designate as "Target" designs, and this should take care of it. Having described the causes here, you can see that very long bearing surface bullets are a potential sore spot for this condition. High velocity and pressures can aggrivate this, but they alone are not totally to blame. One of the worst examples I've ever seen on this occurred (repeatedly and very reproduceably) in a 6.5x55 Swedish Mauser. The outgassing in that combination was so pronounced that the comet tails actually cut the target at 100 yards. Despite this, few of those bullets actually blew up, at least at that distance. A hotter day, a tighter bore, a slightly larger diameter bullet and who knows. Just one of the wierd things you'll see, but yeah, they're out there. </p><p> </p><p>Hope this helps, even if only to explain what's going on.</p><p> </p><p>Kevin Thomas</p></blockquote><p></p>
[QUOTE="Kevin Thomas, post: 288812, member: 15748"] Howdy Tye, Not exactly unheard of, and not too uncommon in some combinations. Berger had some problems with this some time back and have since modified their line to eliminate such problems. You've already touched on part of the answer here; heat. Eric Stecker of Berger Bullets did some very extenisive testing with MIT and high-speed thermal images of bullets in flight to determine what was causing this phenomenon. They took a serious look at the causes here, and spent the time, effort and money to do it right. It comes down to heat, migrating through the jacket and melting the core, or at least a boundary layer of it under the jacket. Once the core goes plastic or liquid, any void in the jacket will allow it to outgas, and the bullet blows. By reviewing the thermal images, Eric was able to discern the actual temperatures of various areas of the bullet in flight, and it's not what you'd automatically expect. The base, for example, stayed quite cool despite being in contact with the hot powder gases. The ogive (not surprisingly) didn't heat up too badly. The real hot spots were the meplat, due to the friction of the air and nose pressure. The worst, though, was the bearing surface, particularly where the rifling was engraved upon firing. This portion hit several hundred degrees, almost instantly. The analysis concluded that the jackets were thin enough to allow the heat to penetrate to the core, and bad things happened. To resolve this, they thickened the jackets to allow for better "insulation" of the core, and the problem now seems to be entirely resolved. Just look for the bullets that they designate as "Target" designs, and this should take care of it. Having described the causes here, you can see that very long bearing surface bullets are a potential sore spot for this condition. High velocity and pressures can aggrivate this, but they alone are not totally to blame. One of the worst examples I've ever seen on this occurred (repeatedly and very reproduceably) in a 6.5x55 Swedish Mauser. The outgassing in that combination was so pronounced that the comet tails actually cut the target at 100 yards. Despite this, few of those bullets actually blew up, at least at that distance. A hotter day, a tighter bore, a slightly larger diameter bullet and who knows. Just one of the wierd things you'll see, but yeah, they're out there. Hope this helps, even if only to explain what's going on. Kevin Thomas [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Bullets vaporizing in mid-air
Top