A: Special Purpose Cartridge.
A: To improve terminal performance over the 5.56 cartridge in short barreld/AR sized weapons for SOCOM forces.
A: During testing the inventors tested a variety of commercial bullets from 6mm, up through 7.62mm. It was found the 7mm bullets provided the best terminal performance while the 6.5 bullets provided the best accuracy. The 6.8 was a compromise between the two. It provided better terminal performance than the 6.5, while having better accuracy than the 7mm prototypes.
A: The 5.56/.223 casing just didn't have enough capacity for the larger round. So the designers chose the now obsolete .30 Remington as the parent case. It provides more capacity than the 5.56 cartridge. The 6.8 SPC case is larger in diameter than the 5.56, but narrower than the 7.62x39 so a new bolt had to be developed, one that is stronger than the 7.62x39 bolt.
A: Short Answer: No, but read the next two Q&As for the full answer.
A: The 6.8 SPC was never inteded to replace the 5.56 for the entire military (though it would be nice), the cartridge was intended for use by Special Operations Forces only.
A: Yes, it's in limited use by SOCOM personel.
A: Barrrel, bolt, and magazines.
A: Not really. while they will work for a few rounds, you really need to buy 6.8 SPC magazines to get capacities over 5 rounds.
A: You get very little increase over 16" so most people opt for the shorter/handier 16" barrels over the 18" (or longer). Barrel should be 4 groove with a 1:11" twist (to keep the pressure at a minium). Older barrels use a 1:10 or 1:9.5 twist rate as that is what is used for the .270 Winchester and is needed for the heavier bullets of that caliber. While the tighter twist rates can be used, you'll limit your 16" velocities to 2500-2600fps.
A: This is a sticky one. You cannot make major with standard factory ammo. However, with an 18" 1:11" twist barrel (Ko-Tonics enhanced chamber recommended) and handloading 120gr Barnes solids or 130gr Speer Softpoints (flatbase) you can make 'Major'. (for details see the Reloading FAQ at the bottom)
A: Right Here: 6.8 SPC Technical Information / Specifications Page
A: YES! The 6.8 uses the same lower. There are NO problems (legal or technical) that prevent you from using your .223/5.56 marked lower with a 6.8 upper
A: The 6.8 uses the same buffers as the 5.56. It will run with anything from the standard CAR buffer to the Rifle buffer (though the ejection pattern will change as the buffer weight changes).
A: Information on reloading for the 6.8 SPC can be found right here: 6.8 SPC Reloading Resource & Information Page
A: At these locations:
Land of the 6.8 - Discussion Forums
Original 6.8 Thread (Archived - Members Only)
6.8 Thread Part II (Archived - Members Only)
6.8SPC.com (Randall's FAQ/List of Links)
2004 NDIA Small Arms Symposium Presentation on the 6.8 SPC (Power Point File)
Wikipedia Entry for 6.8 SPC
A: These vedors carry 6.8 SPC ammo:
Silver State Armory (ammo & brass)
Midway USA (Several Ammo Brands & 6.8 Reloading Components)
The Hunting Shack
Precision Crafted Ammo
ADCO Firearms (often carries ammo)
Sportsman's Guide (occasionally has ammo)
A: These do:
Bushmaster (announced for later this year)
Patriot Ordnance Factory
A: Try these vendors:
Precision Reflex Inc (PRI)
Model 1 Sales
Global Tactical Supply (GTS)
Lewis Machine & Tool (LMT)
A: Yes several companies sell lowers with 6.8 SPC markings:
Grenadier Precision / Leitner-Wise
A: Factory Loads Currently Available as of 29 Aug 07:
Bullseye 110gr V-Max
Hornady 110gr OTM
Hornady 110gr V-MAX
HSM 110gr V-Max
HSM 115gr HPBT Match
Remmington 115gr Core-Lokt Soft Point
Remmington 115gr FMJ
Remmington 115gr OTM ($15.99)
Silver State 110gr Sierra Pro-Hunter Soft Point
Silver State 115gr Sierra Match King OTM
Silver State 110gr Barnes Triple Shock TSX-BT
Thompson Center 120gr Shockwave Ballistic Tip ($32.99)