HKguns, Why did you go with the G1 drag model? I do realize that Sierra lists only the G1 BC's on their website (as does Federal on their shamefully awful website), but the design of the SMK is a much more similar profile to the G7 bullet, and should be more accurately represented by using the the G7 drag model calculations. You might get more accurate long range calculations using the .243 G7 BC (Litz observed) that Brian Litz has published. The observed G7 BC's are also less variable than the G1 across a range of likely muzzle velocities, which may help minimize variances in your actual MV and the MV of the OP.