Calculator for bullets going subsonic?

[Terry]

I'm looking for a calculator to show me when a round goes subsonic.

 

[chromatica]

When a round goes subsonic, the Mach Number falls below 1.0. If your app doesn't give you Mach Number, watch for velocity dipping below 1116 feet per second (at sea level).

 

[dcali]

If you’re interested in long range performance, what you really want to know is when it goes transonic - which is roughly speaking Mach 1.2. That is when you start to see shock wave behavior that is different than you see with supersonic flight, and when aerodynamics start to get weird. You’ll want to avoid that if you can.

 

[DocUSMCRetired]

Our products do this. www.appliedballisticsllc.com

 

[243Mendoza]

For a bullet, any speed above M=1 is supersonic since the flow over the whole bullet is supersonic. For speed less than M=1 but near M=1, there is supersonic flow over portions of the bullet and this occurs a the critical Mach number so I would say transonic flow is between critical Mach number and M=1. Bullet motion due to gyroscopic effects can influence this also. Wind can change this regime range somewhat.

Anyway use, http://www.jbmballistics.com/cgi-bin/jbmtraj_drift-5.1.cgi to find when your bullets goes subsonic, M<1.

 

[Zero333]

I always look for Mach 1.2 to tell me the max distance I can honestly expect the bullet to be 100% true and predictable.

Mach 1.2 is roughly 1,350 fps.

Some bullets fare better than others below 1,350 fps. This is where real world testing comes in.

 

[Terry]

Thanks ti all.

 

[rimfiremac]

Why do you want to know that? It happens a really long ways away from the barrel.

 

[Mr.Knowit all]

I'm pretty sure a DSF is used in subsonic