exposed lead tips burning off???

[konrad]

Hi Folks,

I just received the latest issue of an otherwise reputable magazine (at least I thought they were reputable) and an article there said something like…at modern magnum velocities an exposed lead tip (such as the Sierra Game King) will burn off!!!

I am now wondering at what temperature/velocity will this be a true statement or is this fellow full of … well, you get the idea.

Thanks,
Konrad

[versifier]

What mag/author? I have not read the article in question and would very much like to, but from your statement I think it's a load of fertilizer. Maybe with a rail gun you could get a projectile moving fast enough (over 10,000fps), but never a bullet fired from a normal a centerfire rifle cartridge, even the hottest magnum or wildcat.

Lead's vaporization point is way far above its melting point, and I have never seen, heard of, or read about a bullet melting in flight, even at magnum velocities. To "burn off" the temps would have to get even higher, certainly hot enough to melt the gilding metal cup of the bullet too.

That is not to say that some cup and core bullets won't come apart in flight when fired at velocities much higher than their designed working range, like firing hornet bullets in a .22-250 or a .220Swift. I have seen it happen.

GK bullets are designed to handle magnum velocities, and if you have questions or concerns about the design specs and/or the velocity range of any Sierra bullet, contacting their tech line will get them answered for you.

[konrad]

This month’s Guns and Ammo, Craig Boddington (who I do have a great deal of respect…or should I say “had”), “Deer Bullets 101” is the title of the article.

[konrad]

Good morning Konrad,

Thanks for the email and the question.

I have had this question before and it has no merit. The bullet is not in the air long enough to generate enough heat to cause point deformation from air induced friction.

Now if you have a thin jacket and soft core at extreme velocities it is possible to experience bullet failure induced by the jacket spinning around the core at which point you will see spirals of dark material on the target IF the bullet makes it to the target but that is a whole different set of circumstances.

Rich

Rich Machholz

Ballistic Technician

NRA Life Member
1400 W. Henry St. Sedalia, MO 65301

Questions? Call us toll free 800-223-8799


Check out my latest blog post at sierrabullets.wordpress.com.

[versifier]

Sounds like he's either getting senile or he mixed the wrong meds. Surprising that the editors didn't catch it, but I bet they'll get a lot of negative feedback about it. I stopped getting G&A a long time ago as the quality was on a downward slide. If you are still subscribing send them an email - maybe it will do some good.

[konrad]

Oh yes, by all means, they will be getting a message.

[j1]

Maybe it's a pot stirring expedition meant to bring comments from otherwise silent readers.

[30-40 Kraig]

It wasn't meant to be a tongue in cheek comment was it? I tend to give a fella the benefit of the doubt. But you never know these days with the lack of common since and drive by journalism that does not get fact checked. Its interesting that he would mention Sierra by name.

[Mike in tx]

Which issue of G&A is this in. I just checked April and May issues and can not find the article.

[Hellrazor]

It isn't complete BS. I know the 220swift had issues with this many many moon ago. But that was during a whole different era of bullets.

I will advance the notion that stating a rate of twist is only a simple way to communicate the rotational speed that is required to stabilize a bullet. Twist rates are an expression of a means to an end. I say this only because a static twist rate does not result in a constant rotational speed as rotational speed will vary with the velocity of the bullet. A bullet's rate of rotation has to be fast enough to provide the gyroscopic inertia necessary to stabilize a bullet so that its longitudinal axis tracks true to its intended path and is devoid of yaw. Spin a bullet too fast and there are consequences. Tight twist rates increase bore friction and therefore accelerate barrel wear. In a publicly aired failure analysis conducted by Berger Bullets, that company cited thin jackets and elevated bore friction as a source of lead core melting temperatures that resulted in bullet failure. Bullet rotational speeds can be increased through tighter twist rates to the point radial forces can exceed the strength of a bullet and cause it to fragment in flight prior to contact with a target.

ref - http://www.realguns.com/Commentary/comar175.htm