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Long Range Hunting & Shooting
I am very dissapointed with Berger bullets regarding the 338 hybrid bullet.
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<blockquote data-quote="Eric Stecker" data-source="post: 399718" data-attributes="member: 8908"><p>To clarify, high pressure causing nose slump is on the top of our list but we do not have a clear cause so it could be something else. I relay that there was minimal testing but there was and continues to be ongoing testing.</p><p> </p><p>In these tests there has been one repeatable result. In high pressure loads the bullets drop more than predicted by our BC (even our revised BC). We've observed drop that is consistent with a BC as low as .700. I am a big believer in the scientific process and this process must start with a theory arrived upon by available observations.</p><p> </p><p>When a bullet consistently drops more than expected there are only a few things that can create this result and they are all related to the shape of the bullet. We have compelling physical evidence that the BT is not changing shape. Even if it were it would not produce the amount of change in trajectory that has been observed.</p><p> </p><p>So then we're left with the nose. For many years prior to his death, we worked regularly with Bill Davis (creator of the VLD design). Those who don't know who Bill is think of someone as sharp as Bryan with many decades of testing experience at Aberdeen and Picatinny. He was one of the top minds in external ballistics. </p><p> </p><p>We worked with Bill while we were exploring the bullet failure situation. Early in these bullet failure discussions we were considering nose slump as a cause proposed by Henry Childs. Bill relayed that he had observed nose slump in everything from rimfire to artillery rounds. He said that in every case nose slump was caused by the high pressure spike upon ignition of the powder. </p><p> </p><p>Since this was true even with rimfire ammo it was clear to him that it was not a function of velocity but rather high pressure. We all agree that typically high pressure is associated with high velocity but they are not directly connected. Some rifles produce high velocity at lower pressures than with other loads that produce lower velocity with higher pressures.</p><p> </p><p>Bill said that the conditions that cause nose slump do not cause bullet failure so it was dismissed but never forgotten. Now back to our observations. Nose slump can change the shape of the ogive to the point where the trajectory is affected. We expected this result to be more random but this has not been the case. This is a long answer to your question but this is why nose slump from high pressure is the cause we are investigating first.</p><p> </p><p>Keep something in mind, there are two different situations that have occured with our 338 cal 300 gr. The first is that we jumped the gun and published a BC that is higher than actual (.891 vs. .818) by 7%. The second is that in high pressure situations this bullet will drop more than the .818 BC will predict and the precision will be poor. </p><p> </p><p>The first situation is unfortunate but survivable as this BC is still higher than any other 338 cal bullet available. Remember that our estimation of the .9 BC was based on design. We worked to make the bullet as close as possible to the design but we fell short (not Bryan's fault). We have not made the VLD bullet yet which should have a higher BC than the Hybrid. The second situation affects those who were planning on shooting this bullet hard and must be resolved.</p><p> </p><p>Regards,</p><p>Eric</p></blockquote><p></p>
[QUOTE="Eric Stecker, post: 399718, member: 8908"] To clarify, high pressure causing nose slump is on the top of our list but we do not have a clear cause so it could be something else. I relay that there was minimal testing but there was and continues to be ongoing testing. In these tests there has been one repeatable result. In high pressure loads the bullets drop more than predicted by our BC (even our revised BC). We've observed drop that is consistent with a BC as low as .700. I am a big believer in the scientific process and this process must start with a theory arrived upon by available observations. When a bullet consistently drops more than expected there are only a few things that can create this result and they are all related to the shape of the bullet. We have compelling physical evidence that the BT is not changing shape. Even if it were it would not produce the amount of change in trajectory that has been observed. So then we're left with the nose. For many years prior to his death, we worked regularly with Bill Davis (creator of the VLD design). Those who don't know who Bill is think of someone as sharp as Bryan with many decades of testing experience at Aberdeen and Picatinny. He was one of the top minds in external ballistics. We worked with Bill while we were exploring the bullet failure situation. Early in these bullet failure discussions we were considering nose slump as a cause proposed by Henry Childs. Bill relayed that he had observed nose slump in everything from rimfire to artillery rounds. He said that in every case nose slump was caused by the high pressure spike upon ignition of the powder. Since this was true even with rimfire ammo it was clear to him that it was not a function of velocity but rather high pressure. We all agree that typically high pressure is associated with high velocity but they are not directly connected. Some rifles produce high velocity at lower pressures than with other loads that produce lower velocity with higher pressures. Bill said that the conditions that cause nose slump do not cause bullet failure so it was dismissed but never forgotten. Now back to our observations. Nose slump can change the shape of the ogive to the point where the trajectory is affected. We expected this result to be more random but this has not been the case. This is a long answer to your question but this is why nose slump from high pressure is the cause we are investigating first. Keep something in mind, there are two different situations that have occured with our 338 cal 300 gr. The first is that we jumped the gun and published a BC that is higher than actual (.891 vs. .818) by 7%. The second is that in high pressure situations this bullet will drop more than the .818 BC will predict and the precision will be poor. The first situation is unfortunate but survivable as this BC is still higher than any other 338 cal bullet available. Remember that our estimation of the .9 BC was based on design. We worked to make the bullet as close as possible to the design but we fell short (not Bryan's fault). We have not made the VLD bullet yet which should have a higher BC than the Hybrid. The second situation affects those who were planning on shooting this bullet hard and must be resolved. Regards, Eric [/QUOTE]
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I am very dissapointed with Berger bullets regarding the 338 hybrid bullet.
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