Home Forums Hunting & Shooting Long Range Hunting Do Exposed Lead Tips of Bullets Melt During Flight?

I found some posts on the net where others observed the same thing that I did.

"Lots of years ago I shot both a 223 and a 22-250. I was using a bullet designed for good expansion with the 223 at about 3100 fps. They were designated SX for super explosive. I don't know what brand they were, but when I loaded them to 3800 fps for the 22-250 I got kdub's thin gray streak and they would not hit the hundred yard target. Just not the bullet for that velocity. If you look up Varmit Al's page he has some interesting views of rotational dynamics and spin factors for bullets."

Another.
"There's a write-up in one of the Precision Shooting magaines, suggesting that varmit bullet blow-ups are in fact the result of friction melting the core.

One of the good arguments for this is that, they usually come apart some distance down-range. If it was just a velocity issue, they're going fastest at the muzzle, of course. After a few yards in open air, they'll absorb a lot of heat, though.

Anyway, whether this is true or not, shot plenty of bullets with battered noses, and no practical effect with hunting rifles.

Another article in Rifle or Handloader showed groups fired with ammo that had the noses roughly cut off with wire cutters. Groups were still capable of hitting a deer, as I recall."

anoThink the blow up problem is a combination of roataional energy and jacket weakness. We make the jacket weaker by firing it through a rifled barrel, putting those engravement marks (usually with nice sharp edges). Spin it fast enough, and they can come apart...and would come apart at the weaked sahrp coner first.

Not all rotaional...have shot the same little .40gr. Hornaet bullets in two differtn rifles...one would have them come apoart in mid air (looks like a short length of gray rope for a faction of a second) at 3800fps...the other (same twist) would do it at 3600fps. If ti were just roational, then they'd blow up at the same RPM...so it has to do with how that rifling cuts into the jacket as well.

Don't think bullet tips erode in flight at any kind of common velocity. Have seen little lead sprays surrounding bullet holes when moving bullets close to 4,000fps...but if it's the lead nose, it doesn't do it every time."

What was so much different on other forums where this was discussed is the fact that the tone was polite and informative. There were no personal attacks on any members such as what occurs on this forum at times.

This says volumes about those who made personal attacks in this thread about something that they have never seen.



__________________

Here is some more information that may explain to you on how bullet tips can melt in flight.

web page

I read on the net that Elvis is alive, Martians have landed, Goverment is responsible, and I've won the lottery. If it's on the net, it's got to be true.

Don
Do you lay awake at night worrying about this, or what? All you need do is answer the simple question... where does the magic energy come from to melt the tip?

The energy differential betwixt starting and 100 yards down range does not leave enough lost energy to account for melting the bullet. Then, note the web site you posted included the notations about emisivity. That means the bullet is losing radiant heat (which I had not realized accounted for quite as much energy as it does), in addition to the conductive heat. You should also note the tip in their image is cooler than the sides...

All of that adds up to no melted tips. No matter how you care to pout about the treatment you receive here, you still fail to answer the simple little question. Where does the magic energy come from to melt those tips?
art

Sitka,

I think that I have been treated ok by you as far as I can remember. I don't think about it much or lay awake nights over it. There does seem be be a vandalism here on this site only over things however. As to yourself I appreciate your call for some levity and your efforts at science.

I was waiting for you to anwer my previous posts, twice mentioned that all of the lead does not have to melt to produce melted lead on a target. For instance if a jacket ruptured and some lead toched the bore and that part of the core's lead melted then there would be melted lead on the target.

I really don't think that you have a specific handle on the exact friction in a bore nor the amount of lead that melted.

In any case I observed melted lead on the target. Since it was only that one time with only that one rifle and load I know it is a very rare happening.

I have also now sited Hornady, Sierra and now this photo site as evidence while you are just throwing around an incorrect application of physics.

That post by CAS is evidence of the vanalism that is quite unique to this forum. He has nothing factual to say. Knows little of the topic, has never observed melted lead on a target and yet references a sighting of Elvis.

I am quite disapointed that with all of the evidence that I have presented along with authorities that some reason would come to this forum.

[quote]All of that adds up to no melted tips. No matter how you care to pout about the treatment you receive here, you still fail to answer the simple little question. Where does the magic energy come from to melt those tips?

Art,
----------------------------------------------------------------------
Here is my orginal post "Sierra told me that lead meplats will not melt so I guess it's so but I remain a little suspicious.

Cores will melt however. The Sierra 50 gr Blitz (222R bullet) will melt out of a .219 I. Zipper at 3600 fps. A sprial of lead can be seen around every bullet hole in the target. They don't group well either. "

You will note that I did not say that the tips would melt. In fact I said that I was suspicious of it but that the cores would melt!

Savage,

This horse has been dead and gone for a while........

Beating it further serves no rational purpose.

Give it up already.

Tony

Don
Your lack of a grasp of basic physics is just too sad... I am finished with this thread, so please continue to flog apace and I promise to leave you to your own flagellations...
art

Sitka,

I do appreciate basic physics. The thing is that it must be applied in a correct manner and since it's quite certain that the lead melted and vaporized in my bullets from fractored jackets then your call for proving that all of the core must melt does not apply.

I noticed that you have been camping out on this thread for fun but you still not have replied as to what I really said.

I have now provided more testimony as to the fact that some bullets melt some of the time. I have more such independent testimony that I have saved.

To most of you that doubt that my bullets and the bullets of others including Sierra and Hornady melted just go and load up your 22-250 with some Blitz or SX's and have at it. In addition please call Hornady and Sierra and discuss it with them. Instead of doubting those who have observed it check it out.

Another thing is to remember that as djpainless says "this is all just for fun" Meaning that the shooting sports and rifles in particular are a passion with myself and also all who participate in this and other forums. We can all learn from each other as I sure have learned from you.

Be well.

99

I have in front of me, targets along with load data from 1999......when I tested the 50 grain Blitz in my Remington 700 22-250.

I used the following loads that day:

34.5,35.0 and 35.5 grains of AA2230 lit by a Win mag primer

I also have the test target and load data using the blitz with 36.0 grains of Varget lit by a win mag primer.

Unfortunately, I did not have a chronograph at that time......however, 36.0 grains of varget pushes a 50 grain V-max to 3765 in this rifle, so that will give an idea of how fast I was pushing the Blitz.....

NONE of the targets show any signs of lead comet tails........all the shots made it to the target (no bullets blew up)

I have also shot the 33 grain v-max surplus bullets in this rifle......39.0 grains of varget lit by a WLRM primer pushes that bullet to 4330 fps......all of those bullets have made it to the target and I have recovered the plastic tips and bullet fragments from water filled gallon jugs.......from direct experience on both coyotes and targets, I can tell you the 33 grain v-max has a thinner jacket and is definitely more frangible than the blitz!

I still have more than 100 blitz bullets left (lot #? on the box is 926 114) and I'd be more than happy to load a few up hot, shoot them across the chrono and post photos of the target.......if I thought it would convince you........trouble is, you believe what you want to believe regardless of evidence to the contrary! From your very first post it is clear that you have drawn a conclusion and are now searching for evidence to support it.........real science looks at results and then draws a conclusion.....not the other way around........

I'll throw in my two cents. Though I can not "prove it" my fellow gun scribe and spotter Ed Siemon, while spotting me on 125 grain, HP, .357 bullets fired from a 10 inch Contender chambered for the .357 Herret, saw the bullets turn into gray mist between the muzzle and the 50 yard targets. As I had only loaded 20 rounds for testing purposes we fired all of these rounds with NO impact on target.

As I was shooting a Contender that I knew well, and which shot very well with my hunting loads, and the hand-rifle was topped with a Leupold scope, and the hunting loads, fired following the test loads, printed to point of aim at 100 yards, I have no other answer than the thin jackets of 125 grain HPs dsesigned for the .357 magnum "expanded themselves to death" due to the resistance of the air in the HP causing the cavity to open, peel and self destruct.

This could be off the mark but if you look at the original Hydra-Shok bullets designed by Tom Burczynski, you will note that the center-post in the HP cavity was used to force the liquidous material (flesh) to hydraulicly force open the HP.

Like I said - just my 2 cents worth.

Bluesman

A little mathematics might shed some light.

First, the assumptions.

The heat energy of lead is 128 joules per kg per degree C.
The available energy from a 75 gr. bullet from my 223 WSSM is approximately 2500 joules
The melting point of lead is 327.5 degrees C.
The starting temperature of the bullet is 22.5 C (too low, but good enough)

Using this information, we can calculate it takes 1.24 Joules of energy per degree centigrade to heat a 75 gr bullet.

To reach the melting point of the lead in this bullet (assuming it is 100% lead -- which it isn't), requires approximately 380 Joules.

If we assume the bullet hits the ground with 500 joules left, that means 2,000 joules were lost to friction. For illustrative purposes, a rough estimate of the friction between the bullet and the air is 60 G's of decelleration.

It is logical to assume that the heat of this friction is lost approximately even between the air and the bullet.

However, the math shows that the bullet will melt even if 80% of the energy is lost to the air, and only 20% goes to the bullet.

I found it interesting to read the comment that the bullet would not heat up, at all; that all energy was lost to the air. We know this to be false. The SR71 Blackbird flew at speeds approximating our bullet speeds, but at air densities only 10% of ours. Even with those lower densities, the heat of the air-frame reached temperatures high enough to anneal the titanium shell (in excess of 500 degrees C).

Besides, the expression is "slinging hot lead" for a reason. <img src="/ubbthreads/images/graemlins/wink.gif" alt="" /> FWIW, Dutch.

Careful Dutch----real world examples don't fly in this thread. There are some here who don't beleive that you can raise the temperature of both your hand and a piece of pipe by rubbing them together. My example of the space schuttle needing heat shields was a bust----something about aerodynamics not comparable to bullets. Well the Blackbird should be a closer comparison and most of the rules of physics do not have major holes in them. Its all relative and time is an important element.
Just my $.02 worth.

Dutch,

Cool fact about the SR71...........

However, I think the question to be answered is what is the aero drag on the tip of the bullet ? That would determine how much it would heat up.

I disagree with your reasoning. Just question how to prove it mathematically ?

I mean, the drag on the tip of the bullet can't be all that much, compared to the surface area of the entire bullet. the question is how much does the exposed lead tip of the bullet heat up due to air friction. I still haven't seen an explanation that mathematically proves it.

Tony

Please explain how you arrived at this figure????

I'd also like your input regarding the Blackbird.......would it's shell reach 500 degrees C if it's flight only lasted a fraction of a second as is the case with a bullet?.....or, is there a time component that figures into the equation???

I am certainly no physics expert, but I believe that heat is also generated by the compression of air molecules in front of the leading edge of the projectile, which, at supersonic speeds, is subject to erratic measurement. That measurement would be greatly affected by air density, or viscosity, as stated above, in addition to the shape and area of the leading edge.

The 500 joules left was, as stated, an assumption. Nothing more.

Does the tip melt? Don't know. My point was that a very logical case can be made that there is enough energy in the system for it to melt. Now, experimentation is the next step.

Here's another interesting fact to contemplate. Smokeless powder has a chemical energy content of approximately 4,000 Kj/Kg. In a rifle, approximately 3 to 5% of the energy of the powder charge is lost to the system as friction inside the barrel.

Again, a 50/50 split in energy absorbtion from friction (half to the barrel, half to the bullet) indicates that the bullet would be molten by the time it leaves the barrel! Clearly, there is a time limitation in heat transfer into the bullet we have to allow for, but just as clearly, there is a lot of energy (as heat), going into the bullet from the moment it starts moving into the barrel.

The potential (available energy) for melting is clearly present in the system. A skeptical observer however (including me) is not going to be convinced that melting takes place until we design some experiments to prove either way.

So, how about we put our thoughts together, and design an experiment designed to "disprove" that bullet tips melt? JMO, Dutch.

Since 500 is just an assumption.......let's do some investigating and see if your assumption is valid under practical conditions.

Please bear with me.....I'm not a rocket scientist.......and, feel free to correct any mistakes I make.....

Using 2500 Joules of energy you mentioned, and without knowing your bullet's ballistic coefficent, the best I can figure is that your muzzle velocity is approximately 3330 fps......

According to my ballistics program, using the ballistic coefficient of a 75 grain a-max bullet, the retained velocity at 100 yards is approximately 3095 fps.....giving us 1594 ft-lbs of remaining energy........converted to joules, that gives us 2161 joules of remaining energy.......

Since we started out with 2500 joules and finished with 2161.......the loss of energy was 339 joules.....

Now, according to you, it takes 380 joules to melt lead.......

With a loss of only 339 joules of energy from muzzle to target, and even if all the energy lost is the result of heating the air and the bullet .....it seems that the math proves that it is impossible to melt the bullet?????

By the way, your bullet retains 500 joules of energy until somewhere past 950 yards.........<img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

As far as I can see, those numbers are spot on. And yes, I use that particular combo for 600 to 1000 yard varminting, so they are "relevant".

It was just an example. I took a combo I had set up in Quickload, so I had the energy data available. I picked a bullet with a high b.c. (which has less air resistance) to take a "worst case" scenario.

A 40 gr. flat nose would lose just as much energy, but much faster. FWIW, Dutch.

Dutch,

BTW, I had a typo in my response to you, I meant to say that I didn't disagree with you reasoning...brain runs over my fingers on a regular basis.

Still, I'd like to see the mathematical proof that air friction could heat the tip of a bullet enough to melt it. There ain't much drag there.

Tony