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Thread: If you think so, try this.

  1. #21
    Boolit Master JIMinPHX's Avatar
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    Quote Originally Posted by goodsteel View Post
    Now I can't get WW for prices I can afford and I wish I could have one of those buckets back. Kinda makes me sick.
    http://castboolits.gunloads.com/showthread.php?t=26627
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  2. #22
    Banned 45 2.1's Avatar
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    Golly gee. I suggested a series of shots at increasing velocities, recovering the bases and comparing the width of the engravings, predicting that as velocities went up, the engraving width would increase. I didn't say or suggest that the width of the engraving would vary on the same bullet. I said that the engraving width would vary over the SERIES of bullets. BTDT many many times with your series of shots.... didn't happen then either. I suppose you expect the grooves to get wider as you go up. A top end load doesn't show that.

    I had no idea that there was someone out there so smart he could prove me wrong with a single half of a single bullet, but I learn something new all the time. You missed the point entirely................ like some other folks with pet theories here. Lots of Old Wives Tales keep get repeated here much too often. You need to look at the fit of the boolit in the leade, your alloy choice and how you load............ those things effect everything else and give false positives for the UNINFORMED.

  3. #23
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    Quote Originally Posted by goodsteel View Post
    I have always used alloys that I can get easily and I try to make it work.
    Right now I am alloying eutectic solder 63/37 tin/lead with pure lead 50/50
    Do you see a problem with that alloy being shot through a high power rifle?
    Well, Yes. You are apparently using an alloy that is about 31% Sn, and 69% Pb. Carrumba! Terrific waste of Sn! Two % is generally seen as sufficient, and anything over 3% is wasteful. Find some WW's, or even buy some alloy from one of our vendors, to mix with your solder. for rifle boolits. Elmer Keith did a lot with 1/15 Sn/Pb, and that is about as high a percentage of Sn I have heard of being effectively used in casting.
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  4. #24
    Moderator Emeritus/Boolit Master in Heavens Range
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    [QUOTE=45 2.1;1274596]...BTDT many many times with your series of shots.... didn't happen then either. I suppose you expect the grooves to get wider as you go up. A top end load doesn't show that.

    Sure happened with my rifle. VERY pronounced increase in the engraving width of higher velocity / power loads over the engraving on lower power / velocity bullets. This using bullets from the same batch of alloy, the same lot of powder, gas checks, seated to the same OAL, and fired in the same rifle.

    Not only was the engraving width greater, but close examination of the recovered bullets showed etching on the trailing edge of the engraving, suggesting that wear of the leading edge was responsible for the increase. I duplicated this until I got tired of it.

    Would you care to suggest an alternative explanation?
    Last edited by Molly; 05-19-2011 at 06:39 PM.
    Regards,

    Molly

    "The remedy for evil men is not the abrogation of the rights of law abiding citizens. The remedy for evil men is the gallows." Thomas Jefferson

  5. #25
    Boolit Master JIMinPHX's Avatar
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    I noticed a little bit of that changing width of engraving when I did trials on some .44mag loads a while back. http://castboolits.gunloads.com/showthread.php?t=81258 I also saw that different powders gave me different amounts of boolit slump at the same velocity.
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  6. #26
    Moderator Emeritus/Boolit Master in Heavens Range
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    Quote Originally Posted by JIMinPHX View Post
    I noticed a little bit of that changing width of engraving when I did trials on some .44mag loads a while back. http://castboolits.gunloads.com/showthread.php?t=81258 I also saw that different powders gave me different amounts of boolit slump at the same velocity.
    Thanks for the confirmation. I took a look at your reference and photos, and it looks like you don't have a 'little bit' of engraving enlargement, you seem to have quite a bit. I also notice that 45-2.1 is well aware of your results. I guess we're BOTH wrong, since 45-2.1 says it doesn't happen.
    Regards,

    Molly

    "The remedy for evil men is not the abrogation of the rights of law abiding citizens. The remedy for evil men is the gallows." Thomas Jefferson

  7. #27
    Banned 45 2.1's Avatar
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    [QUOTE=Molly;1274929]
    Quote Originally Posted by 45 2.1 View Post
    ...BTDT many many times with your series of shots.... didn't happen then either. I suppose you expect the grooves to get wider as you go up. A top end load doesn't show that.

    Sure happened with my rifle. VERY pronounced increase in the engraving width of higher velocity / power loads over the engraving on lower power / velocity bullets. This using bullets from the same batch of alloy, the same lot of powder, gas checks, seated to the same OAL, and fired in the same rifle.

    Not only was the engraving width greater, but close examination of the recovered bullets showed etching on the trailing edge of the engraving, suggesting that wear of the leading edge was responsible for the increase. I duplicated this until I got tired of it.

    Would you care to suggest an alternative explanation?
    You haven't made ANY details clear as to what your loading or to what velocities. You sure seem to think it happens to everyone everywhere.

    Quote Originally Posted by Molly View Post
    Thanks for the confirmation. I took a look at your reference and photos, and it looks like you don't have a 'little bit' of engraving enlargement, you seem to have quite a bit. I also notice that 45-2.1 is well aware of your results. I guess we're BOTH wrong, since 45-2.1 says it doesn't happen.
    No..... I suppose you should read what I wrote.... I said it didn't happen to me. I also said your choices caused it to happen to you. See post #11. There are several ways to insure it doesn't happen, but I guess you haven't tried those yet.

  8. #28
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    Hi 45-2.1

    >You haven't made ANY details clear as to what your loading or to what velocities. You sure seem to think it happens to everyone everywhere.

    Nor should it be necessary to do so. I've already told you most of the things I kept constant, but I suppose it won't hurt to add a little more. Who knows, you may be able to point out something I've overlooked.

    Let's see. The alloy was linotype cast into a 311291, seated into the throat of a Ruger 30-06, the high end powder & charge was 50.0g and 52.0g IMR 4831, the intermediate charges were same powder down to 40.0g, and the low end velocities were provided by 25.0 & 30.0g IMR 3031. What have I overlooked?

    As to absolute velocities, I don't know, as I didn't have a chronograph at the time. But it doesn't take a great deal of experinece to see that I had the velocity range pretty well covered.

    But even if I had fired and recovered only one round with ANY powder and ANY charge, and recovered a single bullet base with engraving that was noticably wider than the rifling that produced it, my case is proven. But the body of experimental evidence is considerably greater than that. A phenomenon of abrasive enlargement of engraving has not only been observed, it has been reliably reproduced by myself and demonstrated by others as well. Whether you think that some special conditions applied is immaterial. The enlargement occurred, which is all I ever said in the first place.

    And even if there is some special condition that must be met, the burden of proof is upon you to demonstrate your claim of its existance. You make a lot of noise, but you have yet to produce any alternative theory, or to point out a flaw in mine, or provide the first shred of experimental evidence except that you fired a single shot that didn't demonstrate enlarged engraving. That does absolutely nothing to discredit my observation that enlarged engraving is present in bullets recovered from high velocity rounds from my rifle.

    I'll challenge you back your words. Produce a round under ANY conditions that results in enlarged engraving, and then make "the choices necessary" to produce a highly similar round / velocity that fails to show enlarged engraving.

    ...I said it didn't happen to me. I also said your choices caused it to happen to you. See post #11. There are several ways to insure it doesn't happen, but I guess you haven't tried those yet.[/QUOTE]

    To repeat: Let's see you make some of the choices in a load that aproximates my own that produces enlarged engraving, and then make choices that prevents it.
    Regards,

    Molly

    "The remedy for evil men is not the abrogation of the rights of law abiding citizens. The remedy for evil men is the gallows." Thomas Jefferson

  9. #29
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    This thread appears to have generated considerable discussion on the Accurate Shooting forum for cast bullets. I've tried to respond, but that takes joining, which requires approval, which hasn't occurred yet.

    But one topic over there does deserve some comment here, to avoid misleading someone on this forum. I have been guilty of some carelessness in my description and discussion of enlargement of engraving marks, and have referred to it as 'stripping the rifling.’ This term can be (and is) understood to mean different things.

    I believe it was Col Harrison who reported an attempt to strip the rifling in an American Rifleman discussion of his cast bullet research. If I recall correctly, his attempt to prove or disprove that possibility consisted of inserting a square rod into the muzzle of a rifle and casting a pure lead slug around it. After it had cooled, he tried to rotate the square rod and force the lead slug to strip the rifling. He did not succeed, and concluded that stripping the rifling was an impossibility. And I believe he was right: Cast bullets will not strip from rotary shear so far as I am aware. This is not what I intended to convey by the term, but a fairly extended discussion will be necessary to convey my meaning fully. Please bear with me.

    I found that using ordinary conventional ‘bare’ cast bullet loads, recovered bases from light to moderate power loads were about as I expected and showed engraving widths compatible with the rifling in the gun. Damage to the bullet was nil in the lightest loads, but at a certain power level, small spots of etching appeared on the gas check shank exactly in front of the engraving mark on the gas check. (I still do not understand this: I would expect the first gas leakage to occur in an area NOT compressed by the rifling. But I just report exactly what I found.) These etched spots grew larger with increased power until they formed a ring around the base of the gas check shank. At more or less the same time, etching began to appear on the base band above the gas check shank. Its location was invariably on the trailing edge of the engraving, or on the side NOT being pushed by the rifling to rotate the bullet.

    I can’t define exactly where the engraving enlargement began to take place, but by the time etching had advanced to the second band (again, on the trailing edge), a light but uniform enlargement of the engraving was noticeable. Etching continued to grow progressively worse on the base band as it progressed further up the bullet. And as the etching progressed, so did the enlargement, which was apparently uniform from the gas check as far forward as the condition of the recovered bullet allowed judgment. When the bullet engraving was roughly 170% of the rifling land width, leading spray was observed at the muzzle in a star pattern, originating on the trailing edge of the lands where the etching was. There was no lead / etching spray on the driving side of the lands. Accuracy had seriously deteriorated from a typical 1 to 1.25 MOA to roughly 2.5 to 3.5 MOA. I attribute this enlargement to the more powerful loads producing more pressure on the bullet against the driving side of the engraving. It’s rather like sanding a bit of woodwork: the harder you push, the faster the sandpaper will wear the wood down. Similarly, the harder you push the bullet against the land, the faster the land will wear the bullet.

    From this evidence, I concluded that ‘stripping the rifling’ was entirely possible as an abrasive process. The bullet was being abraded by the driving side of the lands, which resulted in a constantly enlarging engraving on the bullet. The enlarged area acted as a passageway for gas to escape past the body of the bullet, etching lead droplets that were delivered from the muzzle as noted above. By extension, I could envision hotter loads which would abrade the engraving until it merged with the engraving of the adjacent land, leaving nothing of the original body diameter.

    I cannot prove it, but I believe I have actually fired loads that did just this when I first tried cast bullets. I had NO guidance, and I loaded soft lead bullets over a maximum charge for a jacketed bullet in a 30-06. Shooting was quite wild! At 25 yards, I couldn’t even stay on the backstop, and the bore was so badly leaded by just a few shots that no rifling was visible.

    I hope this puts things on a level that isn’t misunderstood by anyone, and apologize for any misunderstandings that may have resulted from my careless wording.

    45-2.1, if this is the source of our disagreement, you have my sincere apology.
    Last edited by Molly; 05-20-2011 at 12:18 AM.
    Regards,

    Molly

    "The remedy for evil men is not the abrogation of the rights of law abiding citizens. The remedy for evil men is the gallows." Thomas Jefferson

  10. #30
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    Originally Posted by goodsteel
    >Now I can't get WW for prices I can afford and I wish I could have one of those buckets back. Kinda makes me sick.

    I haven't tried it, but I understand that some guys have had good success by trading a fresh sixpack (or two) of cold beer for a bucket of dirty tire weights. Your mileage may vary, depending on your sociability index and whether the boss has been selling them ....
    Regards,

    Molly

    "The remedy for evil men is not the abrogation of the rights of law abiding citizens. The remedy for evil men is the gallows." Thomas Jefferson

  11. #31
    Boolit Master

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    Its all good! I think I scored a bucket of WW in trade for some solder. "imagine that!" one of our members said he would deliver right to me. What a deal. Thanks again for setting me strait, I cant wait to try out my guns with this new info.
    I'm so glad I joined cast boolits! This is the best gun sight on the internet!
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  12. #32
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    Frankly, I enjoy it when the guru's battle. It makes me realize how much a babe in the woods I really am.

    Molly, I am not clear, what is your theory as to why you are seeing the engraving increase in width as your velocity increases?

    45 2.1 What do you think is going on?
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  13. #33
    Boolit Master nanuk's Avatar
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    Sao Gan: here is how I understand what Molly is saying

    the vertical edge of the rifling land that is pressured into the lead groove simply WEARS away some of the lead.

    Imagine if you will a rectangle file with cutting one all sides. take a piece of metal , and drive one of the narrow sides into the metal, and with the other hand, pressure the file to one side. the trailing edge will appear to get larger, but it is actually the leading edge (edge where pressure is applied) that cuts the metal.
    the open area left behind (to the side) of the file is where the Leading of the bore originates.

    that is how I understand it

  14. #34
    Boolit Master BABore's Avatar
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    One thing I would be looking hard at is the use of linotype. Sure, it's plenty hard enough at around 22 bhn. It's also extremely brittle without any give, toughness, and elasticity. The increased pressure on the leading edge of the rifling permanetly shifts the material through shearing forces. Shear forces aren't kind to hard, brittle materials. HTWW's would work slightly better, but can still suffer from the same fate if your WW's happen to HT into the 28-30 bhn range. Water dropping WW's will show a slight improvement since it's more apt to produce a slightly softer core if done right. It's also much harder to do on 30 caliber boolits than bigger diameters. Although this doesn't necessarily apply to the OP topic of rifling marks widening and gas blow-by, both lino and WW's have another fault at HV. High antimony levels. At HV you tend to pick up more grey wash in your bbl which is caused by the antimony that has migrated to the boolits exterior. That wash is a hard fouling that reeks havoc on boolits.

    A much better alloy choice would be a mix of 50-50 to 60-40 WW's and Pb, water dropped. Shoot for final hardness of 22 bhn and age the boolits at least a month. The same hardness as lino, but it will have the toughness and elasticity that will tolerate the high torque and shear forces. You also reap the benefits of the lower antimony level and reduced fouling. If even more toughness is needed, add a small portion of nickel babbit to the 50/50 alloy. The small amounts of nickel and copper will increase both hardness and toughness.

    The next step would be proper boolit fit. The OP said that the boolit was seated to touch the rifling. That's all good. What about the rest of the boolit. Is the throat filled with boolit? Is the boolit sized big enough so the expanded case doesn't leave the boolit base hanging in the breeze? That wasn't given. The boolit has to get into the bbl straight and with the least amount of damage to give it a fair chance.

    Finally, how you launch the boolit has a big impact on how it takes the rifling. High launch pressure will cause more distorsion and skidding. Getting the boolit into the bbl before it gets hammered is most desirable. The OP's use of 4831 in the 30'06 is a good start. You need a slow for caliber powder to pull it off. But, was it the right powder? Maybe. There's a whole slug of powders in the same burn rate and slower that could also be the one. You just have to try them. It's also sometimes necessary to make use of a compressible plastic buffer to further cushion the boolit base from the high pressure. Lube will also play into this to keep fouling down. Some work better than others.

  15. #35
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    Learning from mistakes is the best way to learn. I find it better sometimes to learn what won't work than to know instantly what won't. I also keep in mind that those rules are for that set of variables.
    I find that shooting cast is a great way to remove the copper from a lightly copper fouled barrel. Seems to work well for me.
    I think the original post makes some interesting points. Yes, a bullet can strip the lands. I don't have any doubt that it can, if driven hard enough. I also think the point about cream of wheat protecting the base shows that leading is a multifaceted evil. I don't think we can say that leading has a single source. Leading in many guns is caused by a variety of factors. The key is finding what is causing the leading in the gun with that load.

    Brae

  16. #36
    Banned 45 2.1's Avatar
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    Let's see. The alloy was linotype cast into a 311291 Another probable ill fitting boolit., seated into the throat of a Ruger 30-06, the high end powder & charge was 50.0g and 52.0g IMR 4831 These charges are below the starting load for jacketed data and no cast data is listed for these in the current Lyman manual. 55.0 gr. lists at 2,564 fps/37,300 C..... these are hardly high end loads., the intermediate charges were same powder down to 40.0g Obvious why your having problems there., and the low end velocities were provided by 25.0 & 30.0g IMR 3031 29.0 gr. is listed as a starting load at 1,710 fps/ 13,900 C. What have I overlooked? Lets see, your loading outside known safe zones with a hard non ductile alloy without determining the proper boolit/throat fit. Your data and results (much like what another member here did) suggests an undersize boolit. Alloy is too hard for the pressure levels you've given........... etc. If you boolit has a sloppy fit, then the results you've given are the result, among other things. Try reading the archives here... they are full of how to do it right (Myself, BABore, 357 Maximum, Dutch4122), not the 1970's approach that you've listed. Sorry, i'm not biting on your entitlement approach / challenge. Don't bother with a reply as you will have to do your own work, like we did.

  17. #37
    Moderator Emeritus/Boolit Master in Heavens Range
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    Quote Originally Posted by nanuk View Post
    Sao Gan: here is how I understand what Molly is saying

    the vertical edge of the rifling land that is pressured into the lead groove simply WEARS away some of the lead.

    Imagine if you will a rectangle file with cutting one all sides. take a piece of metal , and drive one of the narrow sides into the metal, and with the other hand, pressure the file to one side. the trailing edge will appear to get larger, but it is actually the leading edge (edge where pressure is applied) that cuts the metal.
    the open area left behind (to the side) of the file is where the Leading of the bore originates.

    that is how I understand it
    Very well put, Nanuk. That's an excellent illustration. And notice, if you will, that this ties in perfectly with the usually marginal to poor results of cast bullets used in microgroove barrels. The force necessary to rotate the barrel is applied with very shallow rifling, which has a correspondingly low area compressing the engraving wall. Same amount of force applied over less area means more wear, exaggerating the enlargement.

    I have no microgroove barrels to test, but I wonder if anyone out there is interested enough to load and recover bullets from a series in a microgroove barrel. The series should consist of a very light control load, followed by increasingly more powerful loads until accuracy fails. It sure would be interesting to hear what happens.
    Regards,

    Molly

    "The remedy for evil men is not the abrogation of the rights of law abiding citizens. The remedy for evil men is the gallows." Thomas Jefferson

  18. #38
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    [QUOTE=45 2.1;1275758]
    >Let's see. The alloy was linotype cast into a 311291 Another probable ill fitting boolit., seated into the throat of a Ruger 30-06

    You presume too much, 45-2.1. You have absolutely no reason to make such an assumption. The nose of my 311291 could not be forced into the muzzle of my rifle without a good deal of effort. The body was sized to 0.312" because 0.313" would not fit in the throat of my rifle, and required seating the bullet impractically deep, exposing the base to the powder chamber.

    > the high end powder & charge was 50.0g and 52.0g IMR 4831

    >These charges are below the starting load for jacketed data and no cast data is listed for these in the current Lyman manual. 55.0 gr. lists at 2,564 fps/37,300 C..... these are hardly high end loads.
    , the intermediate charges were same powder down to 40.0g

    You are indeed presumptious sir. Please review this thread and show me where I claimed that I was duplicating jacketed loads, or even that I was using a recommended load from Lyman or anyone else. What I said was that I used IMR 4831 powder, and that the highest load I used / tested was 52.0g of that powder, while the lowest load of that powder was 40.0 gr. That statement is factual, and does not require your approval or even your acceptance.

    >Obvious why your having problems there.,

    So provide some of the reasons that you think pertinent. If you can. Any fool can say "you've made obvious mistakes ..." It's a heck of a lot harder to finish that statement with " ... and this is what they are: (1. ... 2. ... 3. ...)"

    >and the low end velocities were provided by 25.0 & 30.0g IMR 3031 29.0 gr. is listed as a starting load at 1,710 fps/ 13,900 C. What have I overlooked? [B]Lets see, your loading outside known safe zones

    (Sigh) 30.0gr of IMR 3031 under a 170g bullet was a standard recipie for 30-30 loads for decades. If you are suggesting that using that charge in a larger case will produce unsafe pressures, .... well, let's just say we disagreee on that too.

    >with a hard non ductile alloy without determining the proper boolit/throat fit.

    Talk about arrogant presumption! Whatever gives you the idea I had to use an alloy or load that you had approved of? I used an alloy and a powder and a charge that gave me the results I wanted in terms of accuracy and power. I had and still have every right to do so. And as I pointed out above, (and counter to your line of presumption) fit for the throat and bore of the rifle had been examined and determined to be nearly optimum.

    >Your data and results (much like what another member here did) suggests an undersize boolit. Alloy is too hard for the pressure levels you've given........... etc. If you boolit has a sloppy fit, then the results you've given are the result, among other things.

    You are absolutely amazing! My boolit could not have been larger and still functioned. But without a single question from you for information about the dimensions of either the bullet or the throat and bore, you are somehow magically enabled to determine that I was using an undersized bullet.

    >Sorry, i'm not biting on your entitlement approach / challenge.

    I have no idea what you are talking about with this one. But then, neither do you, do you?

    >Don't bother with a reply as you will have to do your own work, like we did.

    Oh, I'm sure you would like that response to go unchallenged. Sorta takes the wind out of your sails to have your obvious mistakes and errronous assumptions pointed out for everyone to see, doesn't it? Well, perhaps not. You seem to have enough wind to cover a lot of sailcloth.

    You know, 45-2.1, I have no problem with being criticized - as such. They give me an opportunity to learn more, and God knows, I appreciate it. But you have come into an honest report of what I did and the results I got, and - though it was obvious you didn't have the slightest idea what I was talking about - began throwing your weight around without the first question to be sure you had understood correctly. You rant about all the mistakes I made. So what? I wasn't trying to develop the perfect cast bullet load by your standards, or even by my own. I was only reporting what I did, the results it gave me, and the conclusions I drew from those results.

    If you had come on equally strong but said something like "Have you considered that (X) might have happened?" or "Another explanation for your results could be (X)", I'd have thanked you. And I'd have meant every word. But you haven't contributed anything at all to the discussion. You've told me that the diameters of my bullet and throat /bore are incorrect, but I'm the guy with the micrometer. I KNOW you're off base. ... Let me rephrase that: I KNOW you don't have the slightest idea what you are talking about.

    Now if you don't want to 'bother' with a response, that's fine. In fact, it's more than fine. I can do without input like yours very nicely. But if you do decide to respond, could you throw in a few facts to go along with your assumptions? In particular, I suggest you give up the notion that I have to or should have developed my loads according to criteria that you set. I set my own criteria to satisfy my own interests and needs, not yours.

    You are welcome to question both my logic and my procedures - but not until you ask a few questions to understand what they are.

    I don't often allow myself the luxury of a response like this, but it just doesn't seem right to deprive you of the recognition you seem to have worked so hard to get.

    Molly
    Last edited by Molly; 05-20-2011 at 05:52 PM.

  19. #39
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    Quote Originally Posted by BABore View Post
    One thing I would be looking hard at is the use of linotype. Sure, it's plenty hard enough at around 22 bhn. It's also extremely brittle without any give, toughness, and elasticity. The increased pressure on the leading edge of the rifling permanetly shifts the material through shearing forces. Shear forces aren't kind to hard, brittle materials. HTWW's would work slightly better, but can still suffer from the same fate if your WW's happen to HT into the 28-30 bhn range. Water dropping WW's will show a slight improvement since it's more apt to produce a slightly softer core if done right. It's also much harder to do on 30 caliber boolits than bigger diameters. Although this doesn't necessarily apply to the OP topic of rifling marks widening and gas blow-by, both lino and WW's have another fault at HV. High antimony levels. At HV you tend to pick up more grey wash in your bbl which is caused by the antimony that has migrated to the boolits exterior. That wash is a hard fouling that reeks havoc on boolits.

    A much better alloy choice would be a mix of 50-50 to 60-40 WW's and Pb, water dropped. Shoot for final hardness of 22 bhn and age the boolits at least a month. The same hardness as lino, but it will have the toughness and elasticity that will tolerate the high torque and shear forces. You also reap the benefits of the lower antimony level and reduced fouling. If even more toughness is needed, add a small portion of nickel babbit to the 50/50 alloy. The small amounts of nickel and copper will increase both hardness and toughness.

    The next step would be proper boolit fit. The OP said that the boolit was seated to touch the rifling. That's all good. What about the rest of the boolit. Is the throat filled with boolit? Is the boolit sized big enough so the expanded case doesn't leave the boolit base hanging in the breeze? That wasn't given. The boolit has to get into the bbl straight and with the least amount of damage to give it a fair chance.

    Finally, how you launch the boolit has a big impact on how it takes the rifling. High launch pressure will cause more distorsion and skidding. Getting the boolit into the bbl before it gets hammered is most desirable. The OP's use of 4831 in the 30'06 is a good start. You need a slow for caliber powder to pull it off. But, was it the right powder? Maybe. There's a whole slug of powders in the same burn rate and slower that could also be the one. You just have to try them. It's also sometimes necessary to make use of a compressible plastic buffer to further cushion the boolit base from the high pressure. Lube will also play into this to keep fouling down. Some work better than others.
    You make some good points BaBore.

    Let me explain that I didn't go the quenched wheelweight route for several reasons. First of all, this work took place decades ago, before water quenching was a widely known process. At least, I didn't know about it. Secondly, it wasn't too long after Col Harrison published the results of his research, where he pointed out that a major factor in cast bullet failure was use of too soft an alloy. Scrap lead was very cheap but very soft. Col Harrison's comment on its use was - if I recall correctly - "Economy is a worthwhile goal, but when it leads you to use materials that guarantee failure, you may wish to re-examine your system of values." Linotype gave me the first reliable loads with power much above what was usable for squirrel hunting, and I turned to it for virtually all powerful loads. and though brittle, it was still quite effective on deer.

    The third reason was that this was not a single unitized research project, at least at first. I didn't set out to find out what the failure mechanisims of cast bullets might be. I just loaded ammo and shot it. Sometimes I could recover bullet bases from dirt banks, pools of water, etc. I'd saved up quite a collection before I noticed that some of them showed varying amounts of etching around the gas check shank. Curious, I made a point of examining the recovered bases, and noticed that the amount of etching was proportional to the power of the load. It was when holding up different recovered bases to compare the etching that I noticed a difference in width of the land engraving as well as a difference in etching. Once noticed, it was embarrassingly obvious, but I'd looked at recovered bullet bases for years without noticing it. It was only when bases with very different engraving widths were held side by side that I saw it. I wonder how much more we see every day, but don't recognize?

    This DID trigger a small research program. I fired (and recovered) linotype 311291 bullets over a range of velocities, and found the progression of etching and engraving enlargement that I reported in preceeding posts. I started with linotype because of the reliability of its results. I stayed with linotype for the simple reason that I didn't want to introduce more variables than necessary. (Geometric progressions grow out of control very quickly!) Once I had a consistent set of results, I thought something to the effect of "Gee, isn't that interesting?" and tucked it away in my memory.

    Oh, I used it from time to time, like when I was developing Cream of Wheat loads. But I didn't number many casters among my friends, and nobody else that cast for rifles. It was just something I knew I'd done, and what the results were, and the conclusions I'd drawn. Then when I started this thread, I put it down here, never dreaming that anything so obvious would draw the attentiion it has received. Or the misunderstanding that some have exhibited.

    By the way, I didn't follow some of your acryronyms: I'm probably showing off my ignorance, but what is 'OP'?
    Last edited by Molly; 05-20-2011 at 05:55 PM.
    Regards,

    Molly

    "The remedy for evil men is not the abrogation of the rights of law abiding citizens. The remedy for evil men is the gallows." Thomas Jefferson

  20. #40
    Boolit Master


    Join Date
    Feb 2010
    Location
    South Western Indiana
    Posts
    1,801
    Molly, OP would be origonal post.
    I am not sure my comment here is part of the consideration here as the loads I will comment on(recovered from snow banks which here are random enough in occurance to hamper establishing results) I have noticed with standard low speed rounds in the '06 using the Lyman 311-291 ( sized to .312) from air cooled WW a slightly wider grouve impression on the leading edge of the first driving band. With the wad cutters in 38 spl from a Smith 66 the widening is more pronouched. When I learned the grease grouves did not need to be in the case neck I no longer noticed the impressions being wider on the front. As I said I don't know if this adds to the discussion but there are two ends to the projectile.
    Don't buy nuthing you can't take home

    Joel 3:10

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check