subsonic 9mm?

The speed of sound in dry air at 20 °C is 343m/s or 1125ft/s. The load that will propel the bullet below this speed (from your pistol) will be subsonic by definition.

Most commercial 115 grain cartridges are supersonic. Most commercial 147 grain are subsonic. Commercial 125 grain are borderline.

When you reload you can easily create subsonic loads with any weight.

Regards
 
i make/sell the 147gr. cast bullet for subsonic use, I believe it is necessary to use this heavy bullet, at that speed or the slide will not co-operate.
 
For a 147 factory load to be supersonic I think you need one of the +P's. I don't think standard 9mm pressure will get a 147 pill over 1125 fps. The 147 white box feels identical to the Law Enforcement Only stuff.
 
All 147grainers are subsonic from pistol length barrels with factory loads. Same factory loads will propel 147 grainers at 1200fps from carbine length barrel.

ian in vic - real question is what bullet is below sonic boom level which is much lower than speed of sound. Bullet gets progressively quieter and more stable in flight from under 1050 fps to some 900-ish fps velocities.
 
My IDPA cartridges using 125 gr cast bullets loaded to around PF 130ish all are subsonic and cycle the slides on all my 9MM guns just fine. It is not necessary to go to 147 gr bullets to go subsonic.

Take Care

Bob
 
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They will still be loud , They are designed for firearms with silencer . The silencer will muffle the expanding gas & being that the bullet is traveling less than the speed of sound you will not here the super sonic crack of a bullet in flight .
 
Lfsabch said:
are they supposed to be quieter? is it noticeable?
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I could never notice the difference in noise level, especially since I always wear muffs. If you want quiet 9mm - forget it, its not 22, too much powder and too short barrel.
 
esquif said:
do a search for special-k on reloading web site. its the standar for 9mm used in supressor
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Special-K uses 158 gr. bullets.

Most factory (non +P) 147 gr. 9mm is subsonic. That's what most guys around here buy to fire through their suppressors. Want a simple load? 3.6gr. of Titegroup with a 147 gr. jacketed bullet. Will be around 985 fps. out of a 5" barrel.

Nothing special about subsonic 9mm loads, just look at the 147 gr. data in any manual.
 
Everything else being equal 124/125 gr bullets should be more accurate than 147 gr bullets in the 9MM due to the twist rate of the barrels.

Take Care

Bob
 
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