.50BMG versus ballistic gelatin block


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Brass Fetcher
September 3, 2006, 11:56 PM
Just got done testing a 750 grain Hornady A-Max .50BMG against a block of ballistic gelatin, with Dave Moore of Spider Firearms providing the gun, ammo and range time.

Write up is at www.brassfetcher.com , attached is a picture of the ~ 2" diameter HOLE at the back face of the 16" long block.

Here is a video of the shot : http://www.youtube.com/watch?v=Qu_IDUH1pmA .

Thank you,

JE223

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beerslurpy
September 4, 2006, 12:27 AM
Wow, I am surprised how early it tumbled. That is a gigantic wound channel, easily enough to take out a whole heart or lung.


Hmm, still no 7.62x39 tests? There are a lot of anecdotes floating around on the subject of the 123 and 154 gr soft points and I think many would appreciate if you ever got around to doing it.

ugaarguy
September 4, 2006, 12:30 AM
JE223, thank you for giving us another great test and write up. Truly impressive.

Stinkyshoe
September 4, 2006, 01:49 AM
JE223
Nice test! That's great! What was your opinion of the Ferret 50?
Thanks
Ss

Brass Fetcher
September 4, 2006, 11:51 AM
I liked the rifle quite a bit - I got the chance to fire it a few times after the test was done. It had a 1-pound trigger pull that was crisp and a recoil that was manageable. That particular gun I was shooting was supposed to shoot 2" at 300 yards - but that's not how well I shot it! :)

The weight of the gun brought the full-on .50BMG cartridge down to the recoil of a 3" magnum 12 gauge. Definately still recoiling, but nothing to be afraid of.

Brass Fetcher
September 4, 2006, 04:24 PM
I got caught up in the Labor Day cheer... and forgot to post a picture of the block. For scale, please note that this is a 10x10 inch rifle block. The block is 16" deep. Pieces of gelatin were laying on the box of sand behind the block. I have never seen detached gelatin at the back of a block before. Truly amazing sight.

Wibb
September 5, 2006, 10:56 AM
WOW. That wound channel is amazing :what:

Wes Janson
September 5, 2006, 02:19 PM
So it began to tumble at 8 inches..interesting. Was anything of the bullet recovered from beyond the sand box?

griz
September 5, 2006, 03:03 PM
Wow! Impressive damage. Did you put anything substantial behind it to try and catch the bullet?

Brass Fetcher
September 5, 2006, 03:54 PM
Hey Griz,

Definately. There was a 12x12x7 inch box filled with wet sand placed behind the block.

The bullet was completely fragmented when it hit the dirt, nothing except for the jacket and core could be found. If so, it would have been in the 12" thick box behind the initial box of dirt - but we sorted through it and didn;t find much.

Brass Fetcher
December 29, 2006, 06:27 PM
A recent email contained a question on the test, regarding my thoughts on the expansion of the aluminum tip of the A-Max bullet, prior to the bullet flipping. The senders asertation was that it likely did deform, similar to what a lead-tipped rifle bullet would do, in the few inches before the bullet flipped over. Here is a picture of the block:
http://www.thehighroad.org/attachment.php?attachmentid=44360&d=1157401475

Notice how the narrowest part of the wound channel is in the first inch or so and then it gets considerably bigger until about 7.8"? If this were just a velocity of the bullet issue, it stands to reason that the track would be largest (before the fragmentation) where the bullet was moving the fastest - at the point where it started to penetrate the block.

So, I figured it like this : the 'magic' that makes a bullet expand is called the 'stagnation pressure', the hydraulic pressure present at the tip of the bullet. Taking the density of water as the density of gelatin, the stagnation pressure was ~ 294MPa, that is 42700 psi acting to squash the aluminum cone at the tip of the bullet. The yield point of aluminum is something like 50MPa, far less 'strength' than is required to resist expansion.

Thank you,

JE223

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