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Old February 7, 2014, 03:21 PM   #1
Sharkbite
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Supressed SBR for HD?

I posted this on another forum, but wanted your guys opinion...

So... My tax stamp should be back this month

Im thinking about changing my "oh CRAP" home defense rifle to my 9" AAC SBR in 300blk with my new SDN-6. Will be about the same length as the 16" .223 im using now.

My question is about ammo for 2 legged animals in 300blk.

Obviously a Sub sonic round would be quieter but im concerned about the heavy bullets not expanding/fragmenting and the subsequent over penetration.

So... What would you guys suggest? Light weight (110gn) bullet driven fast. Still suspressed, but more noisy indoors OR a suspressed subsonic with less bullet performance.
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Old February 7, 2014, 04:10 PM   #2
Bartholomew Roberts
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The 110gr VMAX or TTSX are light years more effective than the subsonics. My personal take is that if I am shooting at an intruder in my house, stopping the threat as fast as possible is my primary goal.

Also, both the subsonics and TTSX will penetrate a lot of ballistics gel, so I think you are right to be concerned about penetration. I think the combination of more demanding shot placement and a lot of penetration make the subsonics less desirable for home defense though.
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Old February 7, 2014, 04:24 PM   #3
Sharkbite
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So i guess thats really the question...

A 300blk subsonic load is usually a 220gn @ 1050fps. About what a HOT 45acp+p puts out energy wise. Nothing wrong with that as a stopper IMO and SUPER quiet

The super sonic stuff IS a lot more powerful.... About 7.62x39ish, but will still be loud indoors

So i guess i stuck on the fence about it. I TOTALLY get the dont worry about your ears if fighting for your life but if i can pre-plan and save both.... Why not?
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Old February 7, 2014, 06:02 PM   #4
JD0x0
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Heavy subsonic essentially = pistol like wounds, with WAY more penetration. You're going to be poking .30 caliber holes and not much more.
Light supersonic bullets will essentially give you the power of a 30-30 or 7.62x39 with expanding projectiles. Generally an impact velocity over 2000fps is needed to cause hydrostatic shock, which can destroy or damage organs that aren't directly in the path of the bullet, which a subsonic bullet just wont do, even with more impact energy than a standard pistol caliber. That energy essentially turns into penetration. If the subsonic bullet is able to expand, it'll simply make a bigger nastier hole but still wont perform like an expanding bullet at 2000+fps.
The only downside to the supersonic bullet is the sonic crack, which isn't terrible, compared to the initial blast of an unsuppressed rifle. Suppressed guns with supersonic bullets still can be surprisingly quiet, and it's going to be a lot quieter than an AR in .223 unsuppressed.

Edit: here's a pretty good example of supersonic versus subsonic in 300AAC. Very quiet, even with supersonic, if you ask me.
https://www.youtube.com/watch?v=hZbxz6ORXFo

Last edited by JD0x0; February 7, 2014 at 06:07 PM.
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Old February 7, 2014, 07:15 PM   #5
Theohazard
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I agree 100% with JD0x0. Using an SDN-6 on both, a supersonic 300 Blackout out of a 9" barrel is quieter than a 5.56 out of a 16" barrel. Inside it's loud enough that it's not comfortable, but it's not so loud that it's going to hurt your ears too much.

I also would really worry about over-penetration with subs; pistol rounds already over-penetrate through interior walls, and I'd worry that the 300 Blackout subs would penetrate even more due to their shape. I recommend using 110 or 115 gr. supers for HD and save the subs for just having fun.
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Old February 16, 2014, 08:31 PM   #6
tmorone
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I've got a 9" AAC 300BLK with a SDN-6 for my "house gun" as well. I run 125gr ballistic tip supersonic ammo through it for the same reasons mentioned above.

-Supersonic loads have much more power, and will reliably expand. Mitigates concern for over penetration.

-Subsonic is super quiet, but the super stuff is not painful to shoot indoors without ear-pro.
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Old February 16, 2014, 08:55 PM   #7
Sharkbite
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I just picked up some more Blacktips, bringing my stock to about 300 rounds. Plenty to function test/prove the gun/load combo and put a good zero on it

I guess the Supers win this contest
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