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

Does the base portion of a partition melt? I've wondered about that.
rimshot

No the base of a partioin does not melt I have recovered them and you could still see the powder engravement of the individual grains in the lead caused by compressed loads

Read some stuff a few years ago on meteors (National Geographic I think), whose velocities would leave most bullets still blinking in the starting gate. When they enter the atmosphere, friction does indeed ionize their surface and we see the resulting light. If a meteor were to rifle straight through the atmosphere, however, and land on your driveway, one could immediately pick it up with no ill effects. Yes, the exterior does heat to ionizing temperatures, but there is insufficient time for heat to transfer to the core. I.e. the core does not have time to accumulate any significant heat energy and they are indeed immediately cold to the touch. Only the thinest portion of the exterior experiences any temperature effects. Street showmen and such often put on displays where appendages are plunged into flame and molten metal with no ill effects. It does indeed take time for heat to transfer. We need some physical chemists or NASA folks to chime in, since they deal with velocities and materials a little speedier than the things we handle. 1Minute

I have not perused this whole thing but I can put a couple of things to rest if they haven't been already. In some years the ocean in this part of the world freezes over in a very smooth flat surface. On those occasions I have fired bullets - mainly from a 30-06- out across the surface aiming for the horizon. That gives the bullet a fairly good run before it begins to skip across the surface. Though it takes some time I have recovered some of these bullets just to see what they looked like. First of all, they don't melt into the snow layer or ice surface so they don't arrive in their final resting place with much heat. They do usually have some snow frozen to them which suggest that they were warmer than freezing temsp when they stopped though.

I have examined bullet jackets and seen lead streaks "soldered" inside adjacent to where hard contact was made with the barrel (rifling). The friction in the barrel does apparently transfer some heat but not a lot.

Plastic and polymer are interchangeable terms, the latter being a bit more accurate and descriptive. Bullet tips, whether acetal resin or whatever, are thermoplastics meaning that heat will make them plastic again. This differs from the thermosetting ploymers like your countertop or pan handles which were made plastic when they were formed and will not become plastic again when heat is applied.

I can promise you that a bullet fired at 600 yards and immediately picked up(not having skidded on ice etc....) is too hot to hold. Hot enough to burn an imprint on your body. And I can bet you know how I know. I can also promise again that we've recovered soft points just fired with the points intact IE not melted. That simply proves one side of the argument. Of course anyone can figure that if the core melted the accuracy would be totally non existant.

The trouble is that any bullet which has stopped at 600 yards was stopped by something other than just losing momentum due to air friction. Therefore it either must have been deformed or was stopped by some substance which would have imparted friction to "siphon off" the remaining energy. Either of those things cause heat just as skipping through snow will produce friction resulting in some heat.

I thought the titanium shell on that plane was tempered to hardness/toughness rather than annealed. Annealing happens at a higher temperature so the assumption that the temps are that high, if they are based on temps required to anneal titanium, would be false. I don't question the heat build up. I don't believe that it gets very high however.

And I have seen the lead "spray" around bullet holes. An interesting thing is that if you shoot the same shape and weight bullet with a sightly heavier jacket at the same speed, (one designed for the high speed and rotational force,) you won't get the gray spray around the holes. Also, those bullets which do spray or streak around the holes, if you shoot them at a cardboard box which is several inches from side to side, those bullets which make streaks going through the first side will often only make particulate holes in the second side because they are so close to coming apart with no impetus other than their own movement.

Klik

So you've done the chemical test to prove the spray is lead? I've seen markings around bullet holes all my life. I"ve never thought they were lead. The only way to prove it is a chemical test of one of those sprays. I still suspect its more a factor of carbon type fouling than actual melted lead. As stated if the lead is melting the accuracy can no longer be maintained IMHO.

Also on the bullet stops at 600. A slow moving bullet that impacts double layers of cardboard target and may or may not have deflected off a berm top or bit of wood frame. I suspect the glance off the berm or wood plus target cardboard would cause some extra heat if anything. Yet no melting of bullet.

I think we may be confusing the ring around the hole, which is often black or dark grey, with a totally different thing, the streaks which sometimes appear - most of the time they don't - when a bullet is starting to come apart. This latter phenomenon only happens when a bullet is at the outer limit or beyond its intended stress range and those streaks are the much lighter grey one would expect to see from powdered lead. Sometimes they also include small pepper sized particle holes which suggest that the bullet is very close to coming completely apart. I have never taken a pic - I wish someone would post one. They have an unmistakeable appearance.

The dark ring around a bullet hole is another interesting question though. I have no idea what that is. Getting used to seeing them from .22 holes when one is just starting out where the lead bullet quite logically leaves a smudge, I guess I never really thought much about why it also happens with jacketed bullets.

I have read many but not all of the posts on this topic so I might have missed the answer to my question. Given what everybody has written about melting lead, etc. What is the blue grey streak I have seen immediately following some lead-tipped, light for caliber, 22-250 bullets ? The bullets have been seen to hit the targets (prairie dogs) but the blue grey streak is also obvious.

if lead melted in bullets than a full jacket as used by the military would not have any lead left in them when they hit the target. as they are open in the base and all the melted lead would run out. yes or no ////

There are many hoary 'old shooters tales' that are without substance.

Bullet deformation is not due to either frictional heating, by air or bore, or aerodynamic heating. It is due to the heat of hysterisis caused by the deformation caused by sudden accelaration.

Photographs show that the tips of bullets are deformed when they exit the barrel, before there is time for aerodynamic friction to take effect.

Nor is the heat of combustion responsible. If it were it would melt the bases lomg before enough heat spread to the tips to cause them to melt. A lead bullet simply has too much mass and conducts heat too slowly for that to happen.

Consider that heat treated lead bullet made of the same alloy as unquenced bullets are far less likely to lead despite their having the same melting point. This increased resistance to powder gases, bore friction, and arodynamic friction is the result of their greater mechanical strength that makes them less susceptible to deformation by setback.to powder gases, bore

Anyone who has ever broken a piece of wire or other metal by rapidly benfing it back and forth has experienced the heat generated. Bullet heating due to setback happens very quickly, in the first inch or two of bullet travel. Unlike heating from an outside source like powder gasses or bore friction, or aerodynamic friction, it does not need to flow from the outside inwards. It occurs simultaneously throughout the bullet. A good analogy is cooking something in a household oven versus a microwave oven.

Also, gas checks do not function by protecting bullet bases from heat. Instead they function like the oil scraper rings on a diesel piston. They scrape off the already deposited residue so the bore will be left clean for the next shot.

bagtic
Some interesting points... not sure there is not some confusion between setback (inertia) and historisis though, which could not/would not happen in the bore... I think...
art

Hubert, absolutely, NO. A bullet starts decelerating the moment it is clear of the gas-jet leaving the muzzle, at a rate of around 60 G's. In an open-based bullet, the lead would be pushing forward, not "leaking out". Kind of like you hitting the seatbelt in a collision. FWIW, Dutch.

Have you ever seen the blue-grey trail coming off the trailing edge of a jet's wing under some conditions? I'm pretty sure that isn't vaporized aluminum. My thought is that the compression and rapid decompression of the air causes condensation of the moisture in the air. I believe that the same thing happens with bullets under some conditions.

only if fired from a 30-30 winchester

Anytime something is physical deformed it becomes heated. A common example is car tires. Tires with low pressure heat up faster than firm tires because the flexing of the sidewalls creates heat just like the flexing of a piece of metal.

This process of creating heat by deformation is an important part of the metalworking process of forging. A piece of metal at room temperature that is impacted by a heavy forging hammer can become too hot to hold.

Bagtic
You are correct, but the energy comes from a hammer blow. A lot of force directed on the metal. The bullet ONLY has the energy it starts with and through friction the kinetic energy is converted to heat. Any vibration the bullet has internally is going to be converted to heat also.

But the problem is the bullet arrives downrange with too much energy left to have converted enough into heat to have melted the lead. And, as was pointed out repeatedly, earlier, the heat is mostly lost to the air and the base of the bullet's vacuum...
art

I can't believe how long this thread has been running! <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

And we still don't have it completely right!!! Some missed a few chapters in the classroom, and some must have missed a couple years, some can't find their common sense, and some can't remember the topic. But yeah, it has been very interesting, entertaining and even a little educational (mostly about people not science).