Long Range Hunting Online Magazine


Go Back   Long Range Hunting Online Magazine > Rifles, Reloading, Optics, Equipment > Rifles, Bullets, Barrels and Ballistics


Reply

The Army Test New Long Range Bullet

 
LinkBack Thread Tools Display Modes
  #1  
Old 04-05-2009, 11:43 AM
Platinum Member
 
Join Date: Feb 2005
Location: USA
Posts: 2,598
The Army Test New Long Range Bullet

U.S. Army Team Tests Radical New Dimpled Bullet « AccurateShooter.com Bulletin



At the U.S. Army’s Aberdeen Proving Ground, a team of ballistics technicians, supported by some of the U.S. Army’s top sniper instructors, has been quietly developing a radical new “dimpled” bullet. The exterior of the bullet resembles the dimpled surface of a golf ball. The function of the special dimpled skin is to reduce projectile drag, providing a flatter long-range trajectory, and greater retained energy at the target.

.338 Projectile with MIM Exo-Jacket
(3D-CAD Artist’s Rendering)



In their pursuit of a lower-drag bullet, the Army tried a variety of designs, including bullets with circumferential drive bands, dual-radius ogives, and rebated boat-tails. The dimpled “golf-ball” design was considered a “long shot” according to the design team, but it has performed beyond all expectations. The nominal drag coefficient (Cd) has improved by about +.040, while cartridge muzzle velocity has increased by nearly 80+ fps because the bullet’s dimpled skin reduces in-barrel friction. What’s more — the terminal performance of the dimpled bullet has been “spectacular”. The Aberdeen team set out to produce a slightly more slippery bullet for U.S. Army snipers. What they ended up with is a bullet with dramatically enhanced long-range ballistics and superior killing power on “soft targets”.

Lt. Col. Ben Eldrick, Long-Range Projectile Project (LRPP) team leader, told AccurateShooter.com how the radical bullet was conceived: “During our initial design work, we wanted the benefits of a high-BC, pointed bullet, but in a design that could be mass-produced and could work as a tracer. We consulted some of the top civilian bullet experts, including ballistician Bryan Litz of Berger Bullets. Mr. Litz really got the ball rolling. He suggested that the ‘next big step’ in bullet design would involve the turbulent boundary layer over the body of the bullet. Litz told us that ‘pointing bullet tips will take you only so far… think about optimizing the airflow over the entire bullet’. That made a lot of sense to us. When you design a race car to be aerodynamic, you sculpt the whole body, not just the front bumper.”



Lt. Col. Eldrick continued: “It turns out Litz was right on the money. By employing a golf-ball type dimpled surface, we were able to optimize the turbulent boundary layer on the bullet body. This reduced the low-pressure wake zone behind the bullet significantly, resulting in reduced base drag. As a result the bullet experiences much less overall drag, effectively raising the BC.” The Army team had discovered that what works for golf balls also works for bullets.



After testing a series of prototypes, the Aberdeen bullet design team settled on a copper-jacketed bullet with dimples about 0.5 mm in diameter. The first-generation bullets were formed in special binary impact swages that press-form the dimples after the bullets were pointed up in conventional dies. Future production bullets will be made with an advanced metal-injection-molding (MIM) process that forms the dimples directly into the surface of the bullets. Rather than simply wrap the core material (which is classified), the MIM is molecularly bonded to the core. The Aberdeen LRPP team calls this “Exo-Jacket” construction, as in “Exo-Skeleton”.

Higher Velocities Achieved

There was a surprise benefit of the dimpled bullet design — higher muzzle velocities. Given the same powder charge, dimpled bullets exit the muzzle faster because they produce less in-barrel friction than do conventional bullets. This is because the recessed dimples effectively reduce the metal-on-metal bearing surface. Lt. Col. Eldrick revealed: “the added velocity was an unexpected bonus. With equal-pressure loads, dimpled .308 bullets will fly about 80 fps faster than normal .308 bullets. With the large .338-caliber projectiles, the difference is even greater… we can pick up nearly 150 fps.” Given the observed velocity gains achieved with dimpled bullets, Aberdeen designers are now working on dimpled shell casings for larger artillery projectiles.



Dimpled Jacket Delivers ‘Explosive’ Fragmentation

While the internal design and core materials of the new dimpled bullet remain classified, the design team revealed that the terminal performance of the new bullet has been “spectacular”. The bullet penetrates like a FMJ but then explosively fragments, resulting in a devastating energy release in the target. According to Capt. Jack Sarazen, an Aberdeen engineer, “the enhanced terminal performance of the dimpled bullet was unanticipated. This was a serendipitous effect of the slight thinning of the jacket material where the dimples are pressed.” Sarazen explained: “Most FMJ bullets break along the cannelure and then fragment into two or three large pieces. With the dimpled bullets, you have multiple fragmentation points so the bullet literally blows up like a grenade in the target.”
__________________
range it,check the wind, dial in correction, aim and only one shot
Reply With Quote
  #2  
Old 04-05-2009, 12:05 PM
Platinum Member
 
Join Date: Jan 2008
Location: SOCIALIST CONTROLLED TERRITORY OF NEW YORK
Posts: 4,388
Re: The Army Test New Long Range Bullet

WOW thats cool I hope it works out for them.
Reply With Quote
  #3  
Old 04-05-2009, 12:44 PM
Platinum Member
 
Join Date: Jan 2003
Location: The rifle range, or archery range or behind the computer in Alaska
Posts: 3,515
Re: The Army Test New Long Range Bullet

Very interesting read. Thanks for sharing.

It will be interesting to see if this becomes a new trend and if so, if it will outlast other trends and become standard for VLD type LR bullets. It definatly could have potential! If the +.040 increase of BC is true, imagine what will become of the 300+ grain 338 bullets.
__________________
Long range shooting is a process that ends with a result. Once you start to focus on the result (where the shot goes, how big the group is, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.
Reply With Quote
  #4  
Old 04-05-2009, 01:17 PM
Gold Member
 
Join Date: Apr 2007
Location: ALASKA
Posts: 504
Re: The Army Test New Long Range Bullet

I believe that article and it's posting to be APRIL FOOLS
Reply With Quote
  #5  
Old 04-05-2009, 05:46 PM
Platinum Member
 
Join Date: Feb 2005
Location: Nevada
Posts: 2,782
Re: The Army Test New Long Range Bullet

jwp475,

That's mighty interesting. Surely wakes you up! :-)
__________________
-----------------------------

-----------------------------
HEBREWS 13:8
Jesus Christ the same yesterday, and to day, and for ever.

Our Lord Jesus said that as it was in the days of Noah and
also as it was in the days of Lot so it shall be in the days...
It's happening again!!! God sent to us His prophet, and His Word
to this generation and we once more are rejecting it as was prophesied!!!

---> As promised, God Sent His Prophet to us!
Reply With Quote
  #6  
Old 04-05-2009, 06:44 PM
Bronze Member
 
Join Date: Apr 2009
Location: South central, Oregon
Posts: 81
Re: The Army Test New Long Range Bullet

I've actually been thinking about that same concept for a few years now. Talked to Dave Corbin about it a couple years ago. Makes perfect sense to me. Seems I read something a while back that made those guys at Jet Propulsion Laboratory and NASA think so to.
Reply With Quote
  #7  
Old 04-05-2009, 06:56 PM
Silver Member
 
Join Date: Jun 2007
Location: Central Washington
Posts: 491
Re: The Army Test New Long Range Bullet

I'm not sure how much boundary layer has at supersonic speeds. Seems like jet fighters, rockets, etc would all be benefitted by dimples if this actually was the case.

It works with golf balls because they have a backspin, not sure how that would work with a bullet. Increasing the air pressure along one side of the bullet would wreak havoc with accuracy.

I love the fact it quotes someone popular here on the boards, a spokesman for Berger, to increase its legitimacy.

I'm calling "Sidd Finch"!

Bill
__________________

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.

Thomas Jefferson

http://waitesandbalances.blogspot.com/
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes


Similar Threads for: The Army Test New Long Range Bullet
Thread Thread Starter Forum Replies Last Post
340 Wby Long Range Bullet Rev. Long Range Hunting & Shooting 2 08-05-2010 09:04 AM
30-06 long range bullet Nomad Reloading 12 05-28-2009 02:58 AM
Ivey 150 moa adjustable rings, initial long range test.... Fiftydriver Equipment Discussions 8 06-01-2006 10:16 AM
First long range test with the 338 Allen Mag.... Fiftydriver Rifles, Bullets, Barrels and Ballistics 62 05-24-2006 10:09 AM

Current Poll
Do You Shoot Rifle Competition?
YES - 33.41%
768 Votes
NO - 66.59%
1,531 Vote
Total Votes: 2,299
You may not vote on this poll.

All times are GMT -5. The time now is 08:36 AM.


Powered by vBulletin ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Management Powered by vBadvanced CMPS
All content ©2010-2014 Long Range Hunting, LLC