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Bumpy Bullets Better?

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Chris Farris View Drop Down
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    Posted: March/19/2010 at 11:04

As published on the shootingwire

http://www.shootingwire.com/

 

Bumpy Bullets Better?

In golf, dimples are the wings of a golf ball. It's not the high coefficient of restitution that gives a ball it's distance, although the compression (that's COR) does help with the slingshotting effect off the club face.

Nope, it's the dimples and their displacement of air that keeps the ball tracking further and straighter.

That's why the number and pattern of dimples are a big deal on a golf ball. Most everything else is marketing, but the dimples really do make a difference in ball flight characteristics.

Technically speaking, it's the result of relocating air and creating a turbulent boundary layer that moves the separation area (the area where the exterior surface of the ball no longer creates friction with the air molecules) further back on the surface.

The result is a thiner wake, making passage through the air easier.

It's all about being more aerodynamic and less of a drag.

We'd heard the U.S. Army was looking into bullet technology with the goal of giving snipers a flatter shooting bullet that was more, well, slippery. Apparently, U.S. Army officials at the Aberdeen Proving Ground have moved bullet technology forward - using some of the principles used in golf-ball technology.

Bullets, if you look at them, have not truly been created for optimal aerodynamic characteristics. The nose of the bullet has changed, but not a lot has happened beyond the nose.

That's the equivalent of making an aerodynamic bumper, but putting the same old square truck behind it.

The Army is now testing changes beyond the nose, evaluating a dimpled bullet that has reportedly reduced projectile drag, yielded a flatter long-range trajectory with much more retained energy at the target.

Their search for "slippery" may have actually yielded the next big break in bullets.

After testing circumferential drive bands, dual-radius ogives, and rebated boat-tails, the dimpled bullet was given a try.

It was the long shot of the group (ouch) - but it absolutely no one expected the performance it has delivered.

Nominal drag coefficients (Cd) have improved- markedly- and muzzle velocities have jumped +80fps in .308 test guns.

Terminal performances have been described as "spectacular" giving snipers a more slippery bullet with enhanced long range performance and way-better results on "soft targets".

In short, the Army's already a potent snipers have been given a better-killing bullet. So much better that some of the dimples in the ongoing tests have come from the smiles on the faces of the testers.

The design for the new dimpled round is reportedly a copper-jacketed bullet with dimples about 0.5mm in diameter. Early tester rounds were produced in binary impact swages that press-formed the dimples after the bullets came from conventional dies.

Next-gen bullets will be made using an advanced metal-injection-molding (MIM) process, putting the dimples directly on the surface of the bullet's jacket. That new high-tech jacket is being called a MIM Exo-Jacket (as in exoskeleton).

The core's composition remains classified.

With lowered drag the dimpled bullets exit barrels faster (due to reduced surface friction). And while the .308's +80fps in added performance is exciting, the higher-pressured .338 is picking up nearly 150fps. That's somewhere impressive and rapidly-approaching awesome. And it's with identical powder charges and cases-the only changes were the dimpled bullets themselves.

And then there's the unexpected bonus.

While full-metal-jacketed bullets break along the cannelure - that band around the cylindrical part of the bullet and fragment, the thinner and more irregular walls of the dimpled bullet have multiple fragmentation points.

Instead of breaking up, the bullet effectively blows up in soft targets. Longer distances, flatter trajectories, increased velocities, and enhanced performance on "soft targets" - sounds like a winner to me.

I always knew whacking hundreds of thousands of golf balls would eventually do me some good. Just never thought they'd be the basis for understanding how engineers were improving bullet performance.

On another note, the feedback from last week's three-part feature on "mouse guns and penlights" has apparently struck a note with readers - and manufacturers.

We've heard from many of you wanting to know the best loads for the small guns, and we're working on that. We have also been told by "highly placed sources" that there will be even more "mouse gun" news at the NRA Annual Convention in May.

Don't have many details - yet- but it's safe to say there will be even more mini-and micro- concealed carry selections to choose from.

Finally, we have confirmed several of the big distributors are finally getting popular caliber ammunition back in stock.

We're also hearing that prices are also starting to fall a bit. Not to price points before the "Obama bounce" last year, but certainly enough that many price-conscious shooters may actually start thinking about heading back to the range.

We'll keep you posted.

--Jim Shepherd

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Post Options Post Options   Thanks (0) Thanks(0)   Quote 300S&W Quote  Post ReplyReply Direct Link To This Post Posted: March/19/2010 at 11:20
  Interesting.  I've been wondering what the next tech advancement would be to increase velocity.  Less drag,kinda like Barnes' triple groove.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SVT_Tactical Quote  Post ReplyReply Direct Link To This Post Posted: March/19/2010 at 16:06
That would be a weird looking bullet. but interseting none the less.  I will volunteer as a tester!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SD Dog Quote  Post ReplyReply Direct Link To This Post Posted: March/19/2010 at 17:02
http://accurateshooter.wordpress.com/2009/04/10/dimpled-bullet-spoof-continues-to-fool-web-readers/

Looks like an April fools prank from last year.


Sorry Chris if I just Pyro'd your post.  Was looking for pics as I had bit and found this.


Edited by SD Dog - March/19/2010 at 17:03
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Chris Farris Quote  Post ReplyReply Direct Link To This Post Posted: March/19/2010 at 17:13
Sad Pacer
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 300S&W Quote  Post ReplyReply Direct Link To This Post Posted: March/19/2010 at 17:50
 
    Ditto 
 
 
 
 
 
    There oughta be a law!!!!!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jonoMT Quote  Post ReplyReply Direct Link To This Post Posted: March/19/2010 at 18:28
I was thinking it was a little early for April Fools jokes. If it will make you feel better, I will try to shoot a golf ball next time I'm out on the range.
Reaction time is a factor...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mike650 Quote  Post ReplyReply Direct Link To This Post Posted: March/19/2010 at 18:34
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 300S&W Quote  Post ReplyReply Direct Link To This Post Posted: March/19/2010 at 18:40
 
  That'll teach em'!!!!!!!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote helo18 Quote  Post ReplyReply Direct Link To This Post Posted: March/19/2010 at 22:52
Read the whole thing.  Was going to ask where the pics were, but then saw it was a fake.  Not a cool thing to do.Baseball Bat
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SVT_Tactical Quote  Post ReplyReply Direct Link To This Post Posted: March/20/2010 at 07:29
Originally posted by helo18 helo18 wrote:

Read the whole thing.  Was going to ask where the pics were, but then saw it was a fake.  Not a cool thing to do.Baseball Bat
 
I was excited too man, your not alone. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sgt. D Quote  Post ReplyReply Direct Link To This Post Posted: March/20/2010 at 07:45
Yea, I was thinkin next we will see dimpled jets, planes and why aren't the UFO's dimpled. Oh well, maybe I'll experiment with the design myself. It helped on a car for Myth-busters why not everything else. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote trigger29 Quote  Post ReplyReply Direct Link To This Post Posted: March/21/2010 at 08:55
Originally posted by Chris Farris Chris Farris wrote:

Sad Pacer
It's ok Chris. I can make you some if it makes you feel better.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Kickboxer Quote  Post ReplyReply Direct Link To This Post Posted: March/21/2010 at 09:22
Here is an explanation of dimples for golf balls.  It would significantly reduce the predictability of a bullet's trajectory, which is already tough enough...

http://math.ucr.edu/home/baez/physics/General/golf.html
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dale Clifford Quote  Post ReplyReply Direct Link To This Post Posted: March/21/2010 at 22:34
So would that be a 1 or 2 stroke penalty for slicing a shot out of the shooting range?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote trigger29 Quote  Post ReplyReply Direct Link To This Post Posted: March/22/2010 at 12:07
Originally posted by Dale Clifford Dale Clifford wrote:

So would that be a 1 or 2 stroke penalty for slicing a shot out of the shooting range?
Depending on where it ends up, they may measure the penalty in years.??

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Post Options Post Options   Thanks (0) Thanks(0)   Quote trigger29 Quote  Post ReplyReply Direct Link To This Post Posted: March/22/2010 at 19:14
Originally posted by 300S&W 300S&W wrote:

  Interesting.  I've been wondering what the next tech advancement would be to increase velocity.  Less drag,kinda like Barnes' triple groove.
 
WinkBig Smile


Edited by trigger29 - March/23/2010 at 16:49

"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SVT_Tactical Quote  Post ReplyReply Direct Link To This Post Posted: March/22/2010 at 19:24
What bullets the second one in the picture trigger?
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Edited by mike650 - March/23/2010 at 18:30
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Post Options Post Options   Thanks (0) Thanks(0)   Quote trigger29 Quote  Post ReplyReply Direct Link To This Post Posted: March/22/2010 at 21:47
Originally posted by SVT_Tactical SVT_Tactical wrote:

What bullets the second one in the picture trigger?
Um..........They are custom. Letting the cat out of the bag a bit with that picture. Some day they may be available for purchase. It has a nose cavity like this.


Edited by trigger29 - March/23/2010 at 16:51

"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
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