Home Forums Hunting & Shooting Long Range Hunting Let's talk TRANSONIC!

You fellas went down the rabbit hole with this discussion, hope you enjoy the adventure!

There be a host of issues related to this discussion and frankly every "solution" has its own baggage. I'm going to throw a couple of things at ya to ponder, just for the fun of it.

Supersonic is what it is, but for purposes of this chat figure anything at or more than about Mach 1.3.
Transonic runs from about Mach .8-1.3.
Mach 1 at international standard atmospheric conditions is ~1116 fps.

The matter of bullet stability is commonly referenced to Stability Factor (Sf) which is a measure of gyroscopic stability acting against aerodynamic overturning forces. All conical bullets fly in a circumstance where the center of aerodynamic pressure is forward of the center of gravity. The displacement between the two is quite a bit different as a function of bullet form. RN bullets have little, needle darts have much more. The significance of this relates to the leverage that aerodynamic forces have on one form as compared to the other. Consider the drag curve below. Note how greatly enhanced drag is in the transonic realm. Note as well that the drag diminishes at higher velocity, but the problem is that your bullet begins to slow when it leaves the muzzle. When it hits the T-zone the forces at play get rather brutal and with spitzer forms this often results in upset.



My point is mostly that you can't have it both ways. The other side of the stability issue is that if one has a very high Sg it may induce degraded tractability, which in turn will cause upset.

Boil, boil, toil and trouble......