The .408 Cheytac and 12.7x108mm APDS rounds have unrealistic airFriction values.
.408 CheyTac = -0.00013
12.7x108 APDS = -0.0001
Compared to real life, they are almost impossibly streamlined. Other low-drag bullets such as .338 Lapua or .50 BMG match rounds would have values of -0.0004 to -0.0008.
To match real-life ballistic data, the .408 Cheytac should have an airFriction of around -0.00042.
The 12.7x108mm APDS should have an airFriction somewhere in the range of -0.00030 -0.00035 to -0.00037 (or thereabouts, APDS data is hard to find).