At what speed in F.P.S. is supersonic.

[GlockCop]

Im not a math whiz and even if I was I forget the speed at which the sound barrier is broken. So in terms of F.P.S. what speed does a bullet need to stay under to stay sub-sonic?

 

[poopgiggle]

It depends on atmospheric conditions, but according to Wikipedia:

In dry air at 20 °C (68 °F), the speed of sound is 343.2 metres per second (1,126 ft/s).

 

[BadgeBunny]

GC said okay ... thanks!! (He also says he is gonna sue me for custody of the computer! LOL)

 

[DANNY-L]

fps x 0.6818=mph if that helps

 

[alank2]

Hi,

You have to also keep in mind that ammo has a "range" of velocity.

A load for example, might average out at 1100 fps, but have a range from 950 to 1050 fps. This is a large extreme spread example, but it just goes to show that 90% of the rounds shot might be subsonic and some supersonic.

Also, some powders are temperature sensitive and you may find they go supersonic in the summer when it is hot if they are on the edge...

Good luck,

Alan

 

[WhiteyMacD]

In dry air, @ 68degF:
anything above 1,126 ft/s is supersonic.

But to keep out of a physics class, lets say anything loaded under 1000/1050fps target and you should be good (as long as your gun will still cycle, of course).

 

[338Shooter]

I shoot for 1050 fps on mine. Anything over that is too dependent on the weather/location.

 

[Ksmirk]

1050fps is a good point to go with. I've got some 308 loads with 165gr cast bullets that are just fun! I set my sights on 1050fps and well I got to 1060fps and called it good. Just remember to start high and work your way down! don't ask me how I know that rule BUT it's a good rule to follow. Later,

Kirk