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Rock River Arm 6.8 SPC Complete Midlength A4 Upper RRA BCG, Charging Handle Included (LAR-6.8) NO FFL REQUIRED, ships to your door. 6.8SPC was developed for better terminal effects while still having an acceptable long range trajectory. The point of 6.8SPC is: significantly better terminal ballistics against humans and animals to 300 yards and still fit and run reliably in the AR15/M16/M4 platform. The parent case is .30 Remington, shortened to fit the AR15 magazine OAL. This is slightly larger in diameter than .223, so a new bolt is required (included in this complete upper). Magazine capacity is slightly reduced vs. 5.56 in the proper mags. Renowned for their quality, Rock River Arms (RRA) has won many military and agency contracts. RRA was selected by the DEA to provide their LAR-15 carbines after winning one of the most demanding stress test competitions in history. Now you can add the hard hitting 6.8 Special Purpose Cartridge (SPC) caliber to your existing AR-15 with the purchase of this (NON-FFL REQUIRED) upper and a 6.8 magazine (see our Magazine section). No modifications required! FAQ: What is recoil like? Shooting a 16" 6.8SPC barrel with the RRA brake has slightly more recoil impulse than a 16" 5.56mm with no brake. It is more noticeable than 5.56 recoil in rapid fire (e.g. double tap, hammer) and full-auto, but much more controllable than 308 weapons with comparable rates of fire.How can I shoot 6.8SPC out of an AR15? The barrel and bolt are specific to 6.8SPC. Magazine bodies and followers designed to work with 6.8SPC are required. We stock the excellent C Products 25 round 6.8 mags. The upper receiver is standard with the addition of larger M4 feedramp cuts. A standard complete AR15 lower is used.How does 6.8SPC's trajectory compare to caliber X? Since the ballistic coefficient (BC) and muzzle velocity (MV) of 6.8SPC is very similar to 75-77gr 5.56mm and 150gr .308, the trajectories will be almost identical. For other comparisons, plug the MV and BC into the ballistic computer of your choice. Resources:
Guns Magazine, October 2004: "Rock River's DEA Carbine" Article The following article is the best history of 6.8 SPC to date:
The 6.8 SPC, Is it all that? Shotgun News 60(21):4-16. July 31, 2006 External Ballistics, Basics When factory loads are fully developed, an 18" barrel should shoot the 115gr OTM at about 2750fps; the 16" barrel at about 2650fps; and a 12" barrel at just over 2500fps.
The BC of the 115gr Hornady is 0.340. The BC of the 110gr VMAX is 0.362. >> Reference Ballistics, Light & Fast 5.56mm
_BC_ _MV_ 0 100 200 300 400 500 600 700 800 | YARDS
0.324 3100 > -2.55 0.00 -1.85 -9.24 -23.35 -46.26 -79.78 -127.75 -193.01 | > IMI M855 62gr
-0.00 1.00 3.00 5.50 8.75 12.75 17.50 23.00 Qt.MOA
3097 2802 2525 2262 2019 1790 1582 1397 1242 | fps, velocity
0.260 3215 > -2.55 0.00 -1.75 -9.20 -23.98 -48.96 -87.15 -144.30 -225.10 | > SA M193 55gr
-0.00 0.75 3.00 5.75 9.25 13.75 19.75 26.75 Qt.MOA
3211 2838 2492 2170 1878 1608 1379 1195 1066 | fps, velocity
>> Reference Ballistics, Heavy & Slow 223/308
0.395 2670 > -2.54 -0.00 -3.24 -13.54 -32.14 -61.26 -102.56 -159.81 -235.18 | > 223REM Black Hills 75gr 20", chrono'd
0.00 1.50 4.25 7.75 11.75 16.25 21.75 28.00 Qt.MOA
2667 2446 2235 2034 1846 1667 1506 1360 1237 | fps, velocity
0.447 2575 > -2.54 -0.00 -3.56 -14.43 -33.69 -63.38 -104.82 -161.35 -234.58 | > 308WIN FGMM 168gr from AR10 20", chrono'd
0.00 1.75 4.50 8.00 12.00 16.75 22.00 28.00 Qt.MOA
2573 2381 2197 2021 1855 1696 1550 1416 1298 | fps, velocity
>> 6.8SPC Ballistics
0.370 2660 > -2.54 -0.00 -3.36 -14.03 -33.39 -63.96 -107.72 -168.94 -250.23 | > 6.8SPC 110gr VMAX 18", chrono'd
0.00 1.50 4.50 8.00 12.25 17.25 23.00 29.75 Qt.MOA
2657 2422 2199 1987 1789 1603 1439 1293 1176 | fps, velocity
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