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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Ballistics beyond 2000 yds : do we need/trust them?
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<blockquote data-quote="CatShooter" data-source="post: 138867" data-attributes="member: 7"><p>[ QUOTE ]</p><p>CatShooter,</p><p></p><p>Just wanted to add my 2 cents. No idea about lead melting in rifles but I know a lot about the situation in big bore handguns. </p><p></p><p>Main reason for gas checks on lead bullets is to prevent leading by friction to the bore.</p><p></p><p>[/ QUOTE ]</p><p></p><p>Poorly lubricated bullets that are gas checked will still lead the bore. The gas checks have some "scraper" action, but not enough to clean the bore.</p><p>Lead handgun bullets used to lead from "bore friction" no matter what... the grease lubes were kinda efficient, but not very.</p><p></p><p>When the Allox lubes came in, it was a big change - first, cuz the Allox lubes allowed higher velocities then ever before, but the second reason was that it caused people to start thinking seriously about why bullets leaded. The current lubes are about lead proof, if the loads are within sanity.</p><p></p><p>[ QUOTE ]</p><p>That said, on big bore revolvers with compensators such as the Ported Taurus and S&amp;W handguns, lead forms on the ports of these handguns when using lead bullets. Not with gas checked bullets but it does with plain base lead bullets of even hard cast nature which says that there is some lead vapor coming off the base of these bullets to build up on the external surfaces of the porting.</p><p></p><p>[/ QUOTE ]</p><p></p><p>It isn't vapor - if it was, it would be coming out so fast that it would be free of the break before it was cool enough to condense on the walls of the break. Also... the temperature that pure lead makes vapor is 3164.0 °F... gentlemen, that is HOT!!! And alloys require even more temperature.</p><p>The melting point of ballistic steel is 2750°F. So if the temperature is hot enough to vaporize lead, it is more than hot enough to melt steel... but if you look at the ports, there is no steel melting away. </p><p></p><p>The lead that build up on the walls of the break is from the same ol' gas cutting... the end of the bullet passes the opening in the barrel, and the 10,000 to 20,000psi burning gas pases across the tail of the bullet on the way out - this gas is traveling **** fast, and the heat/pressure/velocity pushes off some melted lead which splatters on the walls of the port. If you look carefully at the lead build up, you will see that it is "slag looking". If it was vapor, the look of the lead would be smooth and flaw free.</p><p>There is a big difference in what static hot gas will do, compared to what the same temperature gas will do crossing an edge at several times the speed of sound.</p><p></p><p>The gas checked bullets don't allow the hot gas to cut the edge of the bullet when it passes the port.</p><p></p><p>[ QUOTE ]</p><p>Also, another handgun I am quite familiar with is the Magnum Research Desert Eagle. This is a big gas operated semi-auto handgun designed for the largest handgun magnum calibers of its time. You can get these chambered in 357 Mag, 41 Mag, 44 Mag and 50 Action Express.</p><p></p><p>In the owners manual it STRICTLY forbids the use of any bullet with exposed lead at the base of the bullet. This is because in less then a clip full of rounds with expose lead at the base, the lead vapor will build up in the delicate gas porting vents under the barrel and will turn the handgun into a $2K single shot!!! They are also unable to repair this because there is no way to get in and clean out the lead build up.</p><p></p><p>[/ QUOTE ]</p><p></p><p>Same reason as above... when a lead bullet crosses a port, the hot gas across the edge will splatter lead int the port - very fast. If you were to shoot a bunch of lead bullets from a ported gun into a catch material, you would find that the base of the bullet was fine' but on one edge, there would be a melted bevel... maybe only a 1/4 or 1/2 of a millimeter. But that little bit of lead is enough to gum up the works of a gas operated DE pistol - I had one - it was clugie!</p><p> </p><p>[ QUOTE ]</p><p>So, while I have no experience on rifles as far as testing this it does happen in big bore revolver and semi-auto handguns. If it happens with these applications I do not know why it would not in rifles but thats neither here nor there. Just wanted to point out that in some applications, lead will melt off so some degree off the base of a bullet.</p><p></p><p>[/ QUOTE ]</p><p></p><p>Kirby... what you observed did happen. But sometimes, what we observe and "think" caused it, can lead us in the wrong direction later when we are trying to solve another "sorta related" problem. We take the mis-information and apply it to problem "B", and we can't solve it. So we give up because we are convinced we did what we were supposed to.</p><p></p><p>I read this on another site a few days ago... a new reloader checked into a varmint hunting site. He had just gotten a loader kit for Christmas and asked for some information. He was told by one of the folks, that he shouldn't load at this time of the year, cuz when it warms up in the summer, he'll blow up his gun, loose a hand and loose an eye. The writer goes on to say, "... and I have seen guns blow up many times at my local range".</p><p>The poor new guy was petrified.</p><p></p><p>Of course you and I know this story is pure BS - the rise in pressure from 40 to 80 degrees with some of the more temperature sensitive powders (ball and double base stuck), might be a few percent - so max loads at 40 degrees might have a sticky bolt at 80 degrees. And the new guy could have been told to keep the loads a grain under max (it was a .22-250), or he could have been steered towards one of the single base stick powders like the Hodgdon line.</p><p></p><p>The new guy got bad information, based on rumors that the other guy "thought" he knew about (and creatively elaborated on)</p><p></p><p>[ QUOTE ]</p><p>Back to the debate!! /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif</p><p></p><p>As far as BC changing, no comment, will sit this one out!!</p><p></p><p>[/ QUOTE ]</p><p></p><p>/ubbthreads/images/graemlins/wink.gif /ubbthreads/images/graemlins/wink.gif</p><p></p><p>Look... when someone says that changing the powder or changing the primer will change the BC, it is purely wrong.</p><p></p><p>When you plant that information in someone else's head, they take it with them to shooting, and when they are having a problem at long range, they will be looking in the wrong places for a solution. If he is shooting X load at 3000fps and changed the primer or powder but kept the same velocity, he will have the same tracking... but if he changes the primer or powder, and keeps the 3000fps and there is a second (not so obvious problem) this guy will quit looking for it because he will believe he has ruined his BC... when he might have had a new problem enter to picture, like bedding, or scope issues.</p><p>Then he'll go back to the original primer and when the problem doesn't go away, he is lost, convinced that he has screwed something up. Then he will start looking at lot numbers, cuz he's still convinced that it MUST be the primers, and when that doesn't work, where does he go??</p><p></p><p></p><p>That is why I challenge bad info like that.</p><p></p><p>There are opinions... like which is better a 308 or a 7-08, or a Leupold or a Nikon... and we all have them and mostly they are all valid (for each of us).</p><p></p><p>But when it comes to science, there are no opinions. There are known and proven facts...</p><p>... and there are theories based on "properly collected" observations.</p><p></p><p>All the rest is hearsay and BS.</p><p></p><p>.</p></blockquote><p></p>
[QUOTE="CatShooter, post: 138867, member: 7"] [ QUOTE ] CatShooter, Just wanted to add my 2 cents. No idea about lead melting in rifles but I know a lot about the situation in big bore handguns. Main reason for gas checks on lead bullets is to prevent leading by friction to the bore. [/ QUOTE ] Poorly lubricated bullets that are gas checked will still lead the bore. The gas checks have some "scraper" action, but not enough to clean the bore. Lead handgun bullets used to lead from "bore friction" no matter what... the grease lubes were kinda efficient, but not very. When the Allox lubes came in, it was a big change - first, cuz the Allox lubes allowed higher velocities then ever before, but the second reason was that it caused people to start thinking seriously about why bullets leaded. The current lubes are about lead proof, if the loads are within sanity. [ QUOTE ] That said, on big bore revolvers with compensators such as the Ported Taurus and S&W handguns, lead forms on the ports of these handguns when using lead bullets. Not with gas checked bullets but it does with plain base lead bullets of even hard cast nature which says that there is some lead vapor coming off the base of these bullets to build up on the external surfaces of the porting. [/ QUOTE ] It isn't vapor - if it was, it would be coming out so fast that it would be free of the break before it was cool enough to condense on the walls of the break. Also... the temperature that pure lead makes vapor is 3164.0 °F... gentlemen, that is HOT!!! And alloys require even more temperature. The melting point of ballistic steel is 2750°F. So if the temperature is hot enough to vaporize lead, it is more than hot enough to melt steel... but if you look at the ports, there is no steel melting away. The lead that build up on the walls of the break is from the same ol' gas cutting... the end of the bullet passes the opening in the barrel, and the 10,000 to 20,000psi burning gas pases across the tail of the bullet on the way out - this gas is traveling **** fast, and the heat/pressure/velocity pushes off some melted lead which splatters on the walls of the port. If you look carefully at the lead build up, you will see that it is "slag looking". If it was vapor, the look of the lead would be smooth and flaw free. There is a big difference in what static hot gas will do, compared to what the same temperature gas will do crossing an edge at several times the speed of sound. The gas checked bullets don't allow the hot gas to cut the edge of the bullet when it passes the port. [ QUOTE ] Also, another handgun I am quite familiar with is the Magnum Research Desert Eagle. This is a big gas operated semi-auto handgun designed for the largest handgun magnum calibers of its time. You can get these chambered in 357 Mag, 41 Mag, 44 Mag and 50 Action Express. In the owners manual it STRICTLY forbids the use of any bullet with exposed lead at the base of the bullet. This is because in less then a clip full of rounds with expose lead at the base, the lead vapor will build up in the delicate gas porting vents under the barrel and will turn the handgun into a $2K single shot!!! They are also unable to repair this because there is no way to get in and clean out the lead build up. [/ QUOTE ] Same reason as above... when a lead bullet crosses a port, the hot gas across the edge will splatter lead int the port - very fast. If you were to shoot a bunch of lead bullets from a ported gun into a catch material, you would find that the base of the bullet was fine' but on one edge, there would be a melted bevel... maybe only a 1/4 or 1/2 of a millimeter. But that little bit of lead is enough to gum up the works of a gas operated DE pistol - I had one - it was clugie! [ QUOTE ] So, while I have no experience on rifles as far as testing this it does happen in big bore revolver and semi-auto handguns. If it happens with these applications I do not know why it would not in rifles but thats neither here nor there. Just wanted to point out that in some applications, lead will melt off so some degree off the base of a bullet. [/ QUOTE ] Kirby... what you observed did happen. But sometimes, what we observe and "think" caused it, can lead us in the wrong direction later when we are trying to solve another "sorta related" problem. We take the mis-information and apply it to problem "B", and we can't solve it. So we give up because we are convinced we did what we were supposed to. I read this on another site a few days ago... a new reloader checked into a varmint hunting site. He had just gotten a loader kit for Christmas and asked for some information. He was told by one of the folks, that he shouldn't load at this time of the year, cuz when it warms up in the summer, he'll blow up his gun, loose a hand and loose an eye. The writer goes on to say, "... and I have seen guns blow up many times at my local range". The poor new guy was petrified. Of course you and I know this story is pure BS - the rise in pressure from 40 to 80 degrees with some of the more temperature sensitive powders (ball and double base stuck), might be a few percent - so max loads at 40 degrees might have a sticky bolt at 80 degrees. And the new guy could have been told to keep the loads a grain under max (it was a .22-250), or he could have been steered towards one of the single base stick powders like the Hodgdon line. The new guy got bad information, based on rumors that the other guy "thought" he knew about (and creatively elaborated on) [ QUOTE ] Back to the debate!! [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img] As far as BC changing, no comment, will sit this one out!! [/ QUOTE ] [img]/ubbthreads/images/graemlins/wink.gif[/img] [img]/ubbthreads/images/graemlins/wink.gif[/img] Look... when someone says that changing the powder or changing the primer will change the BC, it is purely wrong. When you plant that information in someone else's head, they take it with them to shooting, and when they are having a problem at long range, they will be looking in the wrong places for a solution. If he is shooting X load at 3000fps and changed the primer or powder but kept the same velocity, he will have the same tracking... but if he changes the primer or powder, and keeps the 3000fps and there is a second (not so obvious problem) this guy will quit looking for it because he will believe he has ruined his BC... when he might have had a new problem enter to picture, like bedding, or scope issues. Then he'll go back to the original primer and when the problem doesn't go away, he is lost, convinced that he has screwed something up. Then he will start looking at lot numbers, cuz he's still convinced that it MUST be the primers, and when that doesn't work, where does he go?? That is why I challenge bad info like that. There are opinions... like which is better a 308 or a 7-08, or a Leupold or a Nikon... and we all have them and mostly they are all valid (for each of us). But when it comes to science, there are no opinions. There are known and proven facts... ... and there are theories based on "properly collected" observations. All the rest is hearsay and BS. . [/QUOTE]
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