Posted: 3/6/2012 8:44:05 AM EDT
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We'd all love to do our own calibrated gel tests and have unlimited manufacturer supplied ammo to put through them but that's not gonna happen. O_P uses water jugs as a facsimile. Doc Roberts tells us (through O_P) that penetration in water can be anywhere between 1.6 and 2 times as much as tissue. I wish there were a more exact figure on that. I remember back in the day lots of guys used to test with wet phone books but I don't know how consistent that would be or whether there is a good comparison of penetration in wet phone books vs. penetration in tissue. Anybody know the answer to this? Anybody know any other consistent and cheap method of testing expansion, fragmentation, and penetration?
I'm posting in GD because even though this is kind of an ammo tech question, it's not really a handgun or rifle ammo question. |
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Wet phone books are inconsistent in their make up. Some have thicker paper than others. Some might be "more soaked" than others. That is why they are not good for making comparisons with other testers.
Those testing bullets for penetration and expansion wanted a way for a guy to do tests in California and compare them to tests done by another guy in Maine. The only way to do that is to have an absolutely standardized testing media. Ballistics gelation (10%) properly mixed and held to a standard temperature can be tested by firing a BB at 800 fps and seeing if it penetrates to a standard depth (4 to 5 inches or something like that). If the BB penetrates more or less, the batch cannot be used for standardized testing. By doing that, a test performed in Texas ought to get the exact same results as a test done in South Dakota. And it does. I use water because I don't have a professional lab capable to making and refrigerating the ballistics gelatine. Water isn't as accurate for penetration ( I can only estimate to the nearest 3 inches of depth), but is it easy to use. And I know my tests are "close" to correct as I get the same results as those folks using properly prepared ballistics gelatin. Wish there was an easier way to do the testing, but there is no free lunch. 
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Shot placement is always key.
I'm working up a load for my 10mm and I also want to test a defense load that I've worked up for my AR. I want to know approximately how much penetration I'm getting as well as how much expansion and/or fragmentation. One possible problem is that .40 bullets driven fast sometimes expand too much or fragment and don't achieve sufficient penetration for defense. Of course we are more concerned with where we are causing leaks but assuming the same point of impact, would you rather use a .32 caliber soft lead ball or a .44 caliber GDHP? |
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Quoted:
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One thing to do using water, and assuming O_P's info on 1.6-2x penetration vs. gel, is to fire a known accepted performer for your caliber, get a "reading" off of that and use it as a benchmark for your handload/ bullet selection in that same media/same distance. Consistency/repeatability is key and having a benchmark for comparision can give you can a reasonable result. |
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It will not give results that are comparable to properly calibrated ballistics gelatin. |
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Okay, did a test with the water jugs and chrono.
http://www.ar15.com/forums/t_1_5/1298050_Video_and_pics_of_10mm_and_5_56mm_into_water__Yes__I_m_done_now_.html |