When factory loads are finalized, 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.[2] The BC of the 110gr VMAX is 0.362.[1]
>> 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
0.340 2700 > -2.54 -0.00 -3.28 -13.89 -33.39 -64.57 -109.79 -173.88 -259.95 | > 6.8SPC 115gr OTM 18.0" factory, chrono'd
0.00 1.50 4.50 8.00 12.25 17.50 23.75 31.00 Qt.MOA
2697 2439 2196 1966 1753 1556 1383 1236 1123 | fps, velocity
0.340 2750 > -2.54 -0.00 -3.05 -13.16 -31.79 -61.60 -104.84 -166.17 -248.63 | > 6.8SPC 115gr OTM 18.0" factory, expected
0.00 1.50 4.25 7.50 11.75 16.75 22.75 29.75 Qt.MOA
2747 2486 2240 2007 1792 1590 1414 1261 1142 | fps, velocity
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