New Build 6.8 SPC

[DieselSmoke]

Well w/ all the 6.8 threads lately i decide to go ahead and build one. I've been wanting to for the past few years and ammo seams to be readily available now. Main use is going to be for hogs and coyotes in South and West Texas. I'm still in the desert but iv'e been ordering parts the last few days. So it will be a little while before i have actual build pics but here's the plan so far.

LaRue stripped Lower (which i already had)


Trigger ( CJ's custom job he did for me at Keith's last build party)

Magpul MIAD (FDE)

Stock
Magpul CTR (FDE) w/ the RISR and POD (just cause i like the way it looks) (still need buffer, spring & tube)


Barrel
Wilson Combat "16 SS Fluted, Mid-Lenght 5/8 -24


Troy Claymore Muzzle Brake 7.62


Hand Guard
PRI Gen III Carbon Fiber "9 (FDE) (I already have this one on another gun and i love it)


Optics
Trijicon AccuPoint 3-9X40 w/ a LT104


Still need a few things like:
Bolt Carrier
Gas Block & Tube
Charging Handle
Stripped Upper
Receiver Extension Kit
Harris Bi Pod w/ LT130




Then to top it all off i'm going to Duracoat it similar to this.




So thats the idea, can't wait to get home now and get it together. i'll update this as the build goes along.

[GSXRK5]

What is good about 6.8spc? I've been wondering if it is just something different? Or shoots better? Or what? You can use a regular Lower on those correct? Just need a different (whole) upper?

[motoman]

What is good about 6.8spc? I've been wondering if it is just something different? Or shoots better? Or what? You can use a regular Lower on those correct? Just need a different (whole) upper?

According to Wiki...

The 6.8 mm Remington SPC (or 6.8x43mm) is a rifle cartridge that was developed with collaboration from individual members of US SOCOM.[1] Based upon the .30 Remington cartridge,[2] it is midway between the 5.56x45mm NATO and 7.62x51mm NATO in bore diameter and velocity. It uses a .277 diameter bullet (6.8mm), which is the same diameter bullet as the venerable hunting cartridge 270 Winchester uses. 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 to have a smaller case. The 6.8 mm SPC (Special Purpose Cartridge) has a muzzle velocity of 2,625 feet per second (800 m/s) from a 24 inch (606.9 mm) barrel using a 115-grain Hornady OTM bullet.[3]

The 6.8mm SPC cartridge was designed to address the deficiencies of the terminal performance of the 5.56x45mm NATO cartridge currently in service with the U.S. Armed Forces.[4] The cartridge was the result of the Enhanced Rifle Cartridge program. Participating in the program were U.S. Special Operations soldiers, as well as armorers and other technicians from the United States Army Marksmanship Unit.[5] The development of this cartridge is unusual and interesting in that it was designed by actual shooters in the armed forces, instead of by industry professionals. The goal was to create a cartridge that would bridge the gap between 5.56mm and 7.62x51mm NATO.
The program started the design by using a .30 Remington case, which was modified in length to fit into magazines that would be accommodated by the magazine wells of the M16 family of rifles and carbines that are currently in service with the U.S. Armed Forces.[6]

In tests, it was determined that a 6.5mm projectile had the best accuracy, but a 7mm projectile had the best terminal performance. Further tests showed that a 6.8mm projectile was the best compromise between the two, providing accuracy, reliability and terminal performance up to 500 meters. The combination of the cartridge case, powder load, and projectile easily outperformed the 7.62x39mm Soviet cartridge, with the new cartridge proving to be about 200 ft/s (61 m/s) faster.[7] The resulting cartridge was named the 6.8 Remington Special Purpose Cartridge due to the size of its projectile and the fact that it was based on the .30 Remington case.

The 6.8 mm Remington SPC was designed to perform better in short barreled CQB rifles after diminished performance from the 5.56 NATO when the AR15 was changed from the rifle configuration to the current M4 carbine.[citation needed] The 6.8 SPC delivers 44% greater energy than the 5.56 mm NATO (M4 configuration) at 100–300 metres (330–980 ft). The 6.8mm SPC is not the ballistic equal of the 7.62x51mm NATO cartridge; however, it has less recoil, is more controllable in rapid fire, and lighter, allowing operators to carry more ammunition than would otherwise be possible with the larger caliber round. The 6.8 mm generates around 1,759 ft·lbf (2,385 J) of muzzle energy with a 115-grain (7.5 g) bullet.[citation needed] In comparison, the 5.56x45mm round (which the 6.8 is designed to replace) generates around 1,325 ft·lbf (1,796 J) with a 62-grain (4.0 g) bullet, giving the 6.8mm a terminal ballistic advantage over the 5.56mm of 434 ft·lbf (588 J).[citation needed] In recent developments (the period 2004-2008) the performance of the 6.8 SPC has been increased by approximately 200 ft/s (61 m/s) by the work of one ammo manufacturer and a few custom rifle builders using the correct chamber and barrel specifications.

Q: What does SPC stand for?
A: Special Purpose Cartridge.

Q: Why was the SPC invented?
A: To improve terminal performance over the 5.56 cartridge in short barreld/AR sized weapons for SOCOM forces.

Q: Why 6.8, why not 6.5 or 7.62 mm?
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.

Q: Is the 6.8 SPC just a necked up 5.6?
Q: What is the parent case of the 6.8 SPC?
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.

[motoman]

To the OP, keep us posted on your build. I have plans to build one in the future as well.

[94StangFiveO]

I was going to get one in 6.8 SPC but changed my mind and am building a .300 Blackout upper. Still not sure what lower I'm going to get for it but for now I'm going to use my RRA w/2 stage match trigger. Definitely not going with a high end scope either, I have a cheap Bushnell Trophy XLT or I'll just use my Eotech. It'll use the same muzzle brake as you. It's going to be for hogs and such with plans later to suppress it or a separate one.

Keep us updated because I still am intrigued with the 6.8's.

[Brandon-k]

I'm digging the LT CTR RISR. The cheek weld on my CTR is a little labored right now and that would fix that shit right up. Does it actually function well with the charging handle?

[DieselSmoke]

I'm digging the LT CTR RISR. The cheek weld on my CTR is a little labored right now and that would fix that shit right up. Does it actually function well with the charging handle?

Don't know yet. It's still in the ups box back home. But it's from LaRue so i trust it will.




And i just got the email from CDD. Now i know the exact colors they used on that 700. The base color was French Army Tan. The other accent colors were ACU Dark Grey Green, South African Light Green, Combat Black, and CADPAT Brown. Time to order some DuraCoat.

[no4njnk]

So far the 6.8 has proven itself as a killing machine, 85-110g rounds offer little recoil and have taken down some huge hogs.

[d1tko]

nice
can't wait to built one in that caliber.