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SL1 · November 25, 2009, 10:17 AM

1. I don't think that the fluid in the cavity will be simply "water" at the speed that this bullet is going when it initially hits flesh. The water in the flesh will be heated by the energy of the impact. If the pressure in the cavity is vented to a lower pressure region under the "petal" of the folded-out nose section, then I would expect the hot water to flash to steam at some point as it "flows" from the front of the cavity through the hole. So, the fluid dymanics should get quite complicated to predict. And, THE FLUID DYMANICS COULD CHANGE A LOT WITH DIFFERENT IMPACT MEDIA that has different volatility. For something like this, shooting wax might not give you the same results as shooting a water-based medium. A paper slurry or a ham would probably give more realistic performance measures.

2. With regard to putting something in the cavity that allows expansion without plugging, Hornady has done that. I think it is the same polymer that they use in their "FTX" flex-tip "Leverevolution" ammo, but has a flat-nosed configuration. They call it "Critical Defense" ammunition. It is intended to shoot through clothing without plugging, then expand inside flesh. But, I don't see it available in .45 caliber, so Qball45 may still want to switch away from HPs in his carry ammo for the winter. (But, I would choose wide FPs instead of RNs for personal defense against guys in heavy coats.)

3. They1, please realize that there are plenty of people on this forum that have multiple engineering degrees. We like to SPECULATE about physical processes and TINKER with our gear and components to make our ammo better. But, most of us have found that we really can't predict the effects of these changes from "first principles" of physics and chemistry. There are just too many variables and their interactions are just too complex. Most of our standard predictive processes are based on correlations of data from physical tests. When we tinker, what we really need to do is try things and get good empirical data to guide our efforts. Often, those data confound us because they are not what we expected from our book-educated speculations. And, sometimes our tests give us the results that we expect for reasons that we misunderstand, and we don't find out that we have mislead ourselves until we try the new thing in different circumstances. That kind of education you do NOT get from books - - you get it from experience in trying things out and then dealing with the results. There are a lot of people on this forum who have that kind of experience, too. Some from working with laboratory equipment in the firearms industry and some from other professions. The combination is what keeps me here, because I think it is the best mix available today on the Net. So, if you want to tap the wealth of knowledge on this forum, I suggest that you NOT try to use "credentials" like college degrees and numbers of patents to "trump" a commentor's perspective. That will just cause us to roll out eyes and let this thread die (or at least the part of the thread that will help you). A discussion that sticks to theory and observations can be conducted without getting personal. And, if others do start getting personal, taking the high road and staying out of the egotistical mud will further your cause more than an in-kind response.

Good luck with your development efforts. I am kind of skeptical, but am keeping an open mind. It will be intereting to me no matter how it works-out, so please keep us informed.

SL1

November 25, 2009, 10:17 AM	#34
SL1 Senior Member Join Date: November 8, 2007 Posts: 2,001	A few thoughts: 1. I don't think that the fluid in the cavity will be simply "water" at the speed that this bullet is going when it initially hits flesh. The water in the flesh will be heated by the energy of the impact. If the pressure in the cavity is vented to a lower pressure region under the "petal" of the folded-out nose section, then I would expect the hot water to flash to steam at some point as it "flows" from the front of the cavity through the hole. So, the fluid dymanics should get quite complicated to predict. And, THE FLUID DYMANICS COULD CHANGE A LOT WITH DIFFERENT IMPACT MEDIA that has different volatility. For something like this, shooting wax might not give you the same results as shooting a water-based medium. A paper slurry or a ham would probably give more realistic performance measures. 2. With regard to putting something in the cavity that allows expansion without plugging, Hornady has done that. I think it is the same polymer that they use in their "FTX" flex-tip "Leverevolution" ammo, but has a flat-nosed configuration. They call it "Critical Defense" ammunition. It is intended to shoot through clothing without plugging, then expand inside flesh. But, I don't see it available in .45 caliber, so Qball45 may still want to switch away from HPs in his carry ammo for the winter. (But, I would choose wide FPs instead of RNs for personal defense against guys in heavy coats.) 3. They1, please realize that there are plenty of people on this forum that have multiple engineering degrees. We like to SPECULATE about physical processes and TINKER with our gear and components to make our ammo better. But, most of us have found that we really can't predict the effects of these changes from "first principles" of physics and chemistry. There are just too many variables and their interactions are just too complex. Most of our standard predictive processes are based on correlations of data from physical tests. When we tinker, what we really need to do is try things and get good empirical data to guide our efforts. Often, those data confound us because they are not what we expected from our book-educated speculations. And, sometimes our tests give us the results that we expect for reasons that we misunderstand, and we don't find out that we have mislead ourselves until we try the new thing in different circumstances. That kind of education you do NOT get from books - - you get it from experience in trying things out and then dealing with the results. There are a lot of people on this forum who have that kind of experience, too. Some from working with laboratory equipment in the firearms industry and some from other professions. The combination is what keeps me here, because I think it is the best mix available today on the Net. So, if you want to tap the wealth of knowledge on this forum, I suggest that you NOT try to use "credentials" like college degrees and numbers of patents to "trump" a commentor's perspective. That will just cause us to roll out eyes and let this thread die (or at least the part of the thread that will help you). A discussion that sticks to theory and observations can be conducted without getting personal. And, if others do start getting personal, taking the high road and staying out of the egotistical mud will further your cause more than an in-kind response. Good luck with your development efforts. I am kind of skeptical, but am keeping an open mind. It will be intereting to me no matter how it works-out, so please keep us informed. SL1