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6.8 mm

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diesel View Drop Down
Optics GrassHopper
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Post Options Post Options   Thanks (0) Thanks(0)   Quote diesel Quote  Post ReplyReply Direct Link To This Post Topic: 6.8 mm
    Posted: July/14/2008 at 23:54
guess this is as good place as any to ask. what is the bullet diameter of the 6.8 mm? figures out to be .272, .277 bullets have been around since 1925. is there any advantage to a .005 smaller diameter round? or is this just more military BS? is it a 5.56 necked up or a 7.62 case shortened and necked down? as i could see on the military channel, it looked like an AI with what looks like a 40 deg. shoulder.
there are stupid motorcyclist and there are old motorcyclist but there are no stupid, old motorclclist
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martin3175 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote martin3175 Quote  Post ReplyReply Direct Link To This Post Posted: July/15/2008 at 06:12

The 6.8 mm Remington SPC (or 6.8x43mm) is a new rifle cartridge that was developed with collaboration from individual members of US SOCOM.[2] Based upon the .30 Remington cartridge [3], it is competitor between the 5.56x45mm NATO and 7.62x39mm in bore diameter and velocity with more energy than both. It is particularly adaptable to current 5.56 mm NATO firearms, the cartridge overall length being comparable.

Though ballistically similar to the 1950s-era .280 British, improved propellant powders allow the 6.8 mm a smaller case. The 6.8 mm SPC (Special Purpose Cartridge) has a muzzle velocity in the 2,400 feet per second (730 m/s) range from a 16 inch (406 mm) barrel using a 115-grain bullet.

6.8 on left...223 on right

 

 Performance

The 6.8 mm Remington SPC is designed to deliver 44% greater energy than the 5.56 mm NATO at 100-200 meters.[4] When compared to the more powerful and well-established 7.62x51mm NATO cartridge, the 6.8 mm falls short in all of these areas, but has less recoil and is more controllable. While the 6.8 mm generates around 1,759 ft·lbf (2385 J) of muzzle energy with its 115 grain bullet (note: this figure is from a 24" bolt-action test barrel, not the 14.5 inch barrel of the M4 Carbine), the 7.62 mm NATO (M80) fires a 147 grain bullet at 2,750 ft/s for 2460 ft·lbf of energy (838.2 m/s for 3335 J).

The first major manufacturer to offer a 6.8 mm Remington SPC chambered version of the AR-15 was Barrett Firearms Company, offering the Barrett M468. By 2007, most major manufacturers of AR-15 type rifles for the civilian gun market, such as Bushmaster Firearms International, DPMS Panther Arms and Rock River Arms were also producing 6.8 mm Rem SPC carbines. Ruger Firearms produces a 6.8 mm version of their popular Ruger Mini-14 series carbine [5].

 Muzzle velocity from a 24-inch (610 mm) barrel

  • 7.45 g (115 gr) Full Metal Jacket (FMJ): 2,625 ft/s (800.1 m/s)
  • 7.45 g (115 gr) Boat Tail Hollow Point (BTHP): 2,624 ft/s (799.8 m/s)
  • 7.45 g (115 gr) Sierra Match King (SMK): 2,625 ft/s (800.1 m/s)
Essentially-- the 6.8 spc is a 270 light. It certainly performs better on medium sized game( deer , antelope ) that a 223 , but shots should be limited to ranges around 250yd.s.


Edited by martin3175 - July/15/2008 at 06:19
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