Important notes about data presented in this associated table. First, Sierra lists velocity-dependent effective BCs for each of its bullets – in these velocity regimes and with this type of bullet, effective BC always decreases with decreasing velocity. Nosler provides no such data. As a result, data presented here is significantly skewed in favor of Nosler bullet. Second, 32-grain Sierra BK data is interpolated because external ballistics software used would not allow entries for velocities exceeding 4500 fps – this could certainly introduce minor errors. Finally, 39-grain Sierra BK data is included here mainly for comparison purposes; this is a fine bullet, it does shoot well, and (as demonstrated here) it could certainly be useful for windy day and long range 5/35 SMc applications. Besides having a significant wind drift advantage, it will deliver explosive terminal performance to about 60 yards greater distance. The trouble is, the 39 BK requires a 1/12 twist. Experience suggests that the 32-grain BK will not tolerate these velocities when fired from a barrel with that twist – too bad.

Conclusion
Until Nosler introduces their version of a lightweight 5mm varminting pill, it looks as if the 32-grain Sierra may well be the most efficient such option. The hypothetical (for now) Nosler bullet should be about 30 grains and it could well have a slightly higher BC than the Sierra 32-grain BK. The reason this is feasible is that Nosler uses a solid-base design with a thicker jacket near base of bullet shank. Since gilding metal is significantly less dense than typical core alloys, the solid base and thicker jacket walls increases bullet length (for any given bullet mass). Hence, Nosler can offer a lighter bullet with a longer nose (higher BC) and still have a sufficiently long bearing surface to provide requisite accuracy potential.