How many fps constitutes sub-sonic

[Chokushin]

Hello Gang

Looking for confirmation on how many feet per second constitutes a sub-sonic load. Specifically for 9mm 147gr projectile, I believe it is under 1050fps but I am not 100% certain.

Reason I am inquring is I just bought some factory 9mm 147gr JHP one box of Remington ( which stated they were sub-sonic ) and one box of Winchester Silver Tip which didnt state if they were or weren't. In the past I have used the Winchester Silver Tip 9mm 147gr and the box always stated they were sub-sonic. I am not sure if Winchester just decided not to put this on their newer packaging or if these rounds are not sub-sonic. I did some research in the Winchester catalouge and they list the fps as 1010fps, leading me to believe they are sub-sonic rounds.

Both my Glock 17 and 19 as well as by Browning Hi-Power work great with the Winchester 147gr sub-sonic ammo I have used in the past.I just want to ascertain if this is the same ammo with different packaging or a different non-sub-sonic 147gr JHP that Winchester has put out.

Thanks any and all for your time and I am guessing/hoping I'll be getting responses from Tony and Steyr. I welcome any all others who may be able to shed some light on this question.

[CDunn]

The speed of sound at sea level , dry air= 1,116 feet per second. Slower = Subsonic, Faster = Supersonic, as the words are typically applied to just about anything.

[TicTac]

I just got back from range master school and my instructor said that anything under 1000 fps was sub-sonic. He was probably just ballparking the number though.

[aplonis]

You have your answers above. But here it is again, and rather more...

http://en.wikipedia.org/wiki/Speed_of_sound

What is it you are looking for in a super-sonic projectile...hydrostatic shock? Much of the damage resulting from ultra-high velocity rounds has more to do with their length-versus-diameter ratio which results in very minimal stability from rifling...sufficient only to pass through air without wobbling or even tumbling.

There is another odd effect, the mini sonic boom heard at right angles to a passing bullet. The latter is sometimes attributed as a possible cause in the confusion of shot origin reported by witnesses at the Kenedy assassination. (Or were they hyping the issue?) Supposedly anyone at sufficient distance might hear the mini boom sooner and louder than the muzzle noise, I have read. Thus persons in different places would hear the "shot" as coming from a whole range of different "directions"...and then a later "second" shot.

Just curious,

Gan Uesli Starling
Kalamazoo MI