Subsonic ammo question. 147 gr recommendations.

[jordanvraptor]

Anyone have ideas on 147 gr defensive ammo that will stay subsonic out of an MP5 clone with an Omega 9K? I picked up some fmj but wonder about a jhp load that would be good for confined spaces or from a vehicle.

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• jordanvraptor
• Jan 9, 2026

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[Drew460]

Federal hst will stay subsonic, also the 150 grain federal syntec is the quickest factory ammo I've shot subsonic.

 

[PNWReloading]

Do you own a chrono? Access to one?
This would be your best bet. Most 147gr+ you'll find on the shelf will retain sub but given barrel length you may have to do some testing to verify.


Loading sub 147's for 'farm purposes' I keep them about 900fps. Just enough to consistently cycle the action in an 10" barrel PCC and still quiet enough 50 yards away it sounds like an air rifle.

 

[ilikegunspdx]

Anyone have ideas on 147 gr defensive ammo that will stay subsonic out of an MP5 clone with an Omega 9K? I picked up some fmj but wonder about a jhp load that would be good for confined spaces or from a vehicle.

IMG_4051.jpeg

• jordanvraptor
• Jan 9, 2026

I assume your barrel is not ported (due to using omega)? 147 grain and up will all be subsonic unless you are shooting in very cold temps (and even then with k sized barrel I don't think bullet woudl have enough velocity). Assuming factory ammo, not some hand-made exotic ammo.

If it's a ported barrel (for example if omega is used with a special SD adapter), all ammo will be subsonic, including 124 grain, etc cuz it strips 35%(ish) of the bullet's velocity.

 

[jordanvraptor]

My clone is a standard full size with 8.8" barrel. The MP5SD look is courtesy of a 3D printed handguard from HKBryce and an HK Parts metal and rubber sleeve. Its just a range toy but if I had to grab something out of the safe… I would want it to be hearing safe. I'm leaning toward the Federal HST in 147gr.

 

[ilikegunspdx]

My clone is a standard full size with 8.8" barrel. The MP5SD look is courtesy of a 3D printed handguard from HKBryce and an HK Parts metal and rubber sleeve. Its just a range toy but if I had to grab something out of the safe… I would want it to be hearing safe. I'm leaning toward the Federal HST in 147gr.

Anything 147 or higher would be subsonic unless you were at the North Pole or Siberia.

 

[thatdude1er]

150 Federal Syntech is great and not gassy like a lot of cheaper subs. But like everyone already said, anything 147 and over should stay subsonic unless youre going high up in elevation.

 

[ilikegunspdx]

150 Federal Syntech is great and not gassy like a lot of cheaper subs. But like everyone already said, anything 147 and over should stay subsonic unless youre going high up in elevation.

Syntec is good but I'm not going to use it in 3d foam purposely induced porosity (PIP) cans. The reason being there are tiny pores which clean (carbon etc) super easy with an ultrasonic and breakthrough clean. But that cleaner (and all others I would guess) aren't designed to break down plastic. So plastic fragments from the syntec coating could get lodged in there forever.

Speaking of PIP cans, how about a suppressed mini gun? That woudl be fun. I think they said it is a combo of 3d printed titanium and 3d printed inconel. @Bolt_308 needs one of those.

Cool gun, crappy video of suppressed mini gun imo:

View: https://youtu.be/fT6ue_NGQyY?si=5oHBmM8aPnLiK_X5