Subsonic 9mm other than 147gr?


April 17, 2013, 09:59 PM
Hello THR!

I'm in the process of acquiring my reloading gear, and while I wait I have a 9mm question - 147 gr bullets are sold as "subsonic", but is there any advantage to using them over lower weight bullets that are loaded to subsonic speeds? This is for range / steel shooting with my Glocks and suppressed 9mm AR.

Are the 147s primarily to meet power factor requirements in the various shooting sports, or maybe some increased reliability cycling a cartridge that just fired a heavier bullet at subsonic speeds? Is there something I'm missing?



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Dave Rishar
April 17, 2013, 10:34 PM
Kinetic energy = 0.5 x mass x velocity squared.

Since we've decided that we want to run subsonic, our velocity is fixed at ~1050 FPS at sea level, give or take. Thus, if we want to increase energy, we must increase mass.

I think that the 147gr bullet is the standard because if they get much heavier (more massive) than this, you'll have issues with magazines and COAL.

There is no rule preventing one from using a lighter bullet at a subsonic velocity; you'll simply have less kinetic energy available than you would with a heavier bullet.

EDIT: There are certainly two reasons for using a lighter bullet at a subsonic velocity: less recoil and less raw materials used, so potentially less cost. Other than that and possibly greater availability of bullets, not really.

April 18, 2013, 07:10 AM
Can someone explain the advantages of loading subsonic ammo? I guess I understand if its a suppressed weapon but if not what other advantages.

April 18, 2013, 07:37 AM
In my opinion, their best use is for suppressed weapons. However, I think someone could make an argument for using them in a "truck gun" if the SD use of the weapon would most likely be firing from inside a vehicle. I don't condone the use of reloads for SD, and I have not seen factory loaded subsonic 9mm in the store although it may exist.

They are still loud, but without that crack which is a sonic boom from the bullet breaking the sound barrier.

April 18, 2013, 02:49 PM
Subsonic 147's meet power factors for gun games while having less perceived recoil than a 115g load meeting the same PF. They also make a lot less noise thus the common name of "mouse fart" loads.

April 18, 2013, 10:06 PM
Thanks everybody.


April 19, 2013, 12:41 AM
Yeah, you can make subsonic 115s if you like, but the action won't cycle and the bullet will likely bounce off the cardboard backer, and your target will laugh like a hyena at you.

It's 9mm. Shoot it full pressure or pick up a .22.

April 19, 2013, 11:35 AM
My plan is to make subsonic 124's, since that's all I can find. Hopefully I can make them hot enough to cycle the action of my suppressed AR and be subsonic. Otherwise, they'll get set aside for the pistols.


April 19, 2013, 08:10 PM
I've reloaded 124 grain cast 9mm projectiles subsonic (starting loads) and they worked just fine. Cycled the action and were accurate with no leading. I try to keep those loads around 1150fps, but 900fps will cycle the action of my ruger p95 and Kel-tec PF-9. Not sure how it'll work in an AR though.

April 19, 2013, 08:32 PM
My suppressed 9mm AR runs fine on light loads. They are not gas operated like the rifle calibers.

April 19, 2013, 08:50 PM
Precision Bullets' 147 moly's over bullseye or WSF are my favorite reload for the 9mm. They use less powder then 124gr reloads and are very accurate. I like 'em.

April 19, 2013, 09:08 PM sells Privi 147 gr. SJHP and 158 gr. FMJ

April 19, 2013, 11:58 PM
Mach 1 (speed of sound in the Earth's atmosphere) is 1116 FPS at sea level. As temperature increases , Mach 1 increases and vice-versa. Air density is also a factor.

124's at 1040 fps make 129 PF and shoot very accurately with light recoil.
It's a common load for Production class comp. shooters.

1030 FPS should run okay, but much slower than that may not run the action of some non-modified pistols.

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