# Subsonic pistol loads?



## prof_fate (Jan 2, 2012)

I'm looking for a subsonic formula for reloadin 9mm. I've not found any....I did find some commercial ammo at 950 or so but always with 147gr bullets which I can't find as components...

Also, the FPS listed in manuals and forumulas - is that for the max load, min load, or ??

How does barrel lenght affect it? The only thing I've seen was recent article testing Hornady critical duty ammo in a glock (4.5" barrel) and an XDm (5.25 barrel) where the velocity from XDm's longer barrel was about 5% more or so.


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## rex (Jan 27, 2012)

If you don't have a manual that shows the velocity range try the powder or bullet companies.In general anything under 900 is subsonic,but there are variables that dictate exact speed at a given time and place.I think it can swing from low 800s to over 1k but I'm not sure about that.


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## Steve M1911A1 (Feb 6, 2008)

rex said:


> ...[T]here are variables that dictate exact speed at a given time and place.I think it can swing from low 800s to over 1k but I'm not sure about that.


The variable is atmospheric pressure, I believe.
At sea level, subsonic is any speed below about 1,000 feet per second. (The actual figure is 1,108fps.)

The subsonic loads you've found use 147gr bullets because your pistol requires a recoil pulse of a certain power in order to function, and the only way to get that powerful a pulse with a small powder charge is to project a relatively heavy bullet.
If you use a lighter bullet, say perhaps 125gr, the load's recoil may not be sufficient to operate the pistol's self-loading feature. You would either experience misfeeds and extraction jams, or you would have to rack the gun's slide between shots.


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## hideit (Oct 3, 2007)

off hand i am thinking that the only subsonic pistol cartridge is the .45
all the 9mm and 40 etc are higher velocity
i wonder if a CCI subsonic 22lr cartridge will operate a ruger mkiii -


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## rex (Jan 27, 2012)

Yeah,that's it Steve.Pretty well covers temp,altitude,whatever else.I've heard sea level being in the 9s so it must have been a really cold day when that was calculated.Or is it hot,I never really worried about it.


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## Charlie (May 13, 2006)

prof_fate said:


> I'm looking for a subsonic formula for reloadin 9mm. I've not found any....I did find some commercial ammo at 950 or so but always with 147gr bullets which I can't find as components...
> 
> Also, the FPS listed in manuals and forumulas - is that for the max load, min load, or ??
> 
> How does barrel lenght affect it? The only thing I've seen was recent article testing Hornady critical duty ammo in a glock (4.5" barrel) and an XDm (5.25 barrel) where the velocity from XDm's longer barrel was about 5% more or so.


All the manuals I have indicate a starting load and a max load (with fps for both). Most manuals indicate a barrel length of the test barrel used for the loads they list and it's usually 5" or even longer. A shorter barrel will reduce the fps which would put it "closer" to subsonic.


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## talldrink (Dec 21, 2010)

hideit said:


> i wonder if a CCI subsonic 22lr cartridge will operate a ruger mkiii -


My MKIIs will cycle CCI subs, CCI SV, Winchester subs, Wolf MT....


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## prof_fate (Jan 2, 2012)

talldrink said:


> My MKIIs will cycle CCI subs, CCI SV, Winchester subs, Wolf MT....


How much quieter are they? 
I use the same ammo in my 22 rilfe as I do my Mk1 and the Mk1 is way way louder. Not as loud as the Xdm9 of course.


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## talldrink (Dec 21, 2010)

I believe that my CZ 452 is quieter than the MKs as well. But if you compare HV to SV ammo in the MK the difference is obviously noticeable.


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