Re: Got questions for/about BBTI?

26
gaucheGlock wrote:Hahahahaha!
Jim, you're apologizing for not responding for 1½ months, but I didn't even see your post until two months later! I guess we both have other fish to fry.

My favorite stuff so far on BBTI is the chopped-barrel data, because when one of the barrels happens to be sloppier or more shot-out than the others, it shows up across all the ammo types, and it's relatively easy to correct for.

If there were one thing I could wish for, it would be for access to the raw data. I want to see how many rounds were fired in each test, and in what order. The chrony numbers have some fascinating clues concealed in them, like the way velocity variability increases with how hot the loads are.

If you wanted to post the mean and standard deviation of the velocities that would be great, but I'll pump my own numbers if you give the data.
Don't you mean two months and year! :roflmao:
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Image

"Resistance is futile. You will be assimilated!" Loquacious of many. Texas Chapter Chief Cat Herder.

Re: Got questions for/about BBTI?

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Hopefully, Jim will see this is a month or two:

Since one mission of the Liberal Gun Club is "education," and since many questions about ammo and gun choice come up, it would be nice to make a specific LGC educational page that ties "gun use" with "bullet type/weight" and "effect upon target."

Such a page might look into reduced recoil training loads, self defense loads, hunting loads, long range target loads, long range hunting loads, and so on. I'm thinking a focused page where common LGC educational questions are linked to the proper BBTI data/pics.

CDFingers
Crazy cat peekin' through a lace bandana
like a one-eyed Cheshire, like a diamond-eyed Jack

Re: Got questions for/about BBTI?

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bigmike0301 wrote:Not a thread hijack, but I'd like to see some kind of standardization regarding 'felt' recoil. I have no idea HOW to do this (indentation of ballistic gel, springs, energy per share centimeter) I dunno. Just think it would be a useful scale or number when developing loads, comparing ammo, firearms.
Hmm. Quantify impulse over surface area over time? I forget the terms, it's been years since my last physics class.
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Re: Got questions for/about BBTI?

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Well, CDFingers, I made it in just a couple weeks ... :mrgreen:

And yeah, I like your idea. I'd be happy to help out with it however I can with our data.

bigmike0301 wrote:Not a thread hijack, but I'd like to see some kind of standardization regarding 'felt' recoil. I have no idea HOW to do this (indentation of ballistic gel, springs, energy per share centimeter) I dunno. Just think it would be a useful scale or number when developing loads, comparing ammo, firearms.
This is actually something that the BBTI team has talked about a fair amount, wondering whether we could easily adapt the sort of accelerometers that are used in cell phones. They should be fairly inexpensive, and seem to be pretty accurate ...

You could probably also do something with a classic weighted-sled like physics experiments use, perhaps with a Ransom rest on a track or something.

But we keep coming back to the fact that recoil is VERY subjective, and at least in part depends on how a gun is in contact with the hands/shoulders. A poorly-fitting (or poorly held) gun is going to have a much worse perceived recoil than a much more powerful gun which is held/used properly.

Jim
James Downey

http://www.ballisticsbytheinch.com/ - handgun cartridge research
http://www.stcybiswell.com/ - my latest novel
http://www.legacybookbindery.com/ - my professional site

Re: Got questions for/about BBTI?

31
gaucheGlock wrote:If there were one thing I could wish for, it would be for access to the raw data. I want to see how many rounds were fired in each test, and in what order. The chrony numbers have some fascinating clues concealed in them, like the way velocity variability increases with how hot the loads are.
You got your wish: http://www.ballisticsbytheinch.com/rawdata.html

Shoulda wished for a pony! :roflmao:

(Seriously, we've always had the data sets available, just so people could play with the data in ways we would never think of. And sometimes some very interesting things result from that.)


Jim
James Downey

http://www.ballisticsbytheinch.com/ - handgun cartridge research
http://www.stcybiswell.com/ - my latest novel
http://www.legacybookbindery.com/ - my professional site

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