Quantcast
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

.50BMG versus ballistic gelatin block

Discussion in 'Rifle Country' started by Brass Fetcher, Sep 3, 2006.

Thread Status:
Not open for further replies.
  1. Brass Fetcher

    Brass Fetcher Member

    Joined:
    Jan 11, 2006
    Messages:
    1,685
    Location:
    Eastern border of the United States
    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
     

    Attached Files:

  2. beerslurpy

    beerslurpy member

    Joined:
    Nov 8, 2004
    Messages:
    4,438
    Location:
    Spring Hill, Florida
    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.
     
    Last edited: Sep 4, 2006
  3. ugaarguy

    ugaarguy Moderator Staff Member

    Joined:
    Mar 19, 2006
    Messages:
    12,079
    JE223, thank you for giving us another great test and write up. Truly impressive.
     
  4. Stinkyshoe

    Stinkyshoe Member

    Joined:
    Jan 28, 2003
    Messages:
    539
    Location:
    Midwest
    JE223
    Nice test! That's great! What was your opinion of the Ferret 50?
    Thanks
    Ss
     
  5. Brass Fetcher

    Brass Fetcher Member

    Joined:
    Jan 11, 2006
    Messages:
    1,685
    Location:
    Eastern border of the United States
    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.
     
  6. Brass Fetcher

    Brass Fetcher Member

    Joined:
    Jan 11, 2006
    Messages:
    1,685
    Location:
    Eastern border of the United States
    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.
     

    Attached Files:

  7. Wibb

    Wibb Member

    Joined:
    Jun 30, 2006
    Messages:
    35
    Location:
    Saint Louis
    WOW. That wound channel is amazing :what:
     
  8. Wes Janson

    Wes Janson Member

    Joined:
    May 12, 2006
    Messages:
    1,962
    So it began to tumble at 8 inches..interesting. Was anything of the bullet recovered from beyond the sand box?
     
  9. griz

    griz Member

    Joined:
    Dec 25, 2002
    Messages:
    2,371
    Location:
    Eastern Virginia
    Wow! Impressive damage. Did you put anything substantial behind it to try and catch the bullet?
     
  10. Brass Fetcher

    Brass Fetcher Member

    Joined:
    Jan 11, 2006
    Messages:
    1,685
    Location:
    Eastern border of the United States
    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.
     
  11. Brass Fetcher

    Brass Fetcher Member

    Joined:
    Jan 11, 2006
    Messages:
    1,685
    Location:
    Eastern border of the United States
    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:
    [​IMG]

    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
     
    Last edited: Dec 29, 2006
Thread Status:
Not open for further replies.

Share This Page