Suppressed 5.56 - Sub Sonic

[Texas1911]

 

[Texas42]

Cool. It won't cycle the bolt?

 

[West Texas]

Way Cool!

 

[TimberWolf7.62]

So basically, it's taking a .223 and turning it into a .22 with a slightly heavier bullet.

 

[matefrio]

You could get a 75 grain round subsonic that'd blow any .22lr away in ballistic coefficient and energy.

 

[TimberWolf7.62]

My point was that you kill most of the stopping power of the .223 when you cut the velocity. Taking Remington data found here Remington Ballistics Calculator , a 55 grain bullet at 3,240 fps = muzzle energy of 1282 ft-lbs. Using a ballistic calculator such as this one Muzzle Energy Computer shows that cutting the velocity to subsonic ( http://www.accuratepowder.com/data/...al(5.56mm)/223 Remington pages 185 to 187.pdf ) 1,139 fps gives us a muzzle energy of 158 ft pounds. A 40-gr .22 at the same 1,139 fps gives 115 ft pounds.

Using the 75 gr. .223 at 1,052 fps = 184 ft pounds, or 60% more than the .22. Is this blowing it away? Maybe, but you're still dealing with a .223 with less than .380 performance, so who cares? You've still ruined all of the .223 performance by going subsonic.

 

[matefrio]

You're right... larger caliber may trump the .223. But it's fun after investing $$$ in a .223 platform and suppressor to get that quiet and that performance without much more $$ invested.

It's not common to go above 77 gr. but they do make 90 gr. in that caliber. I don't know if I'd trust a 90gr round be stabilized though.

Once rounds outside the 224 Diameter are considered one could load a .50 bmg 750 gr. subsonic and with a suppressor make one heck of a quiet setup. Then others might argue that a 20mm would be better. :-)

 

[TimberWolf7.62]

There is nothing in my post regarding using a larger caliber.

Actually, I think the whole idea of trying to make a rifle shoot completely silently is, while perhaps an interesting exercise, fairly useless. Rifles mainly gain their power from high velocity - cut that down to subsonic and you kill their power. And for what? I grant that there may be some rare, very specialized situations in which you absolutely have to have it but they're probably about as common as winning the lottery.

The overwhelming majority of military situations in which a suppressor is used are served sufficiently with full power ammo, so that the suppressor conceals the muzzle blast. The enemy hears the rounds coming in but cannot locate the source. Once a couple of rounds come in, the enemy is going to know they're under fire anyway, even if they are totally silent.

 

[navyguy]

I never occurred to me anyone was worried about the stopping power of that sub sonic round. Seems to me it's for plinking and maybe small varmint shooting. It should be more accurate than a 22LR shot out of a .223 barrel, but that is just an assumption, and accuracy may go the other direction because the odd things that can happen when you go to extremes in velocity.

 

[30+GSXR]

hmmmmm, I own and run the Gemtech G5 on my rifle and it states in the manual NOT to use sub-sonic ammo.

 

[Texas1911]

I think it has more to do with being a quiet round, and thus fun and different, not really it's ballistics.

 

[baboon]

I'll stick with my .300 whisper in the AR platform

 

[West Texas]

Think of all you save on hearing protection

 

[SC-Texas]

Messiah had some 100grn 556 that operated the action.

 

[matefrio]

where did he get his from...?

I found this:

Extreme Shock Subsonic Covert-Ops Specialty Ammunition 223 Remington 100 Grain ASP Full Cycling

Googling will get you some vendors.

 

[7WSM]

If anyone knows where to get the bullets, let me know.

 

[SIG_Fiend]

Hey G, check Sierra and Berger. They both make some from 80-90gr. Berger has VLD's from 70gr to 90gr:

Berger Target Bullets

Sierra Bullets - The Bulletsmiths

 

[7WSM]

The problem with the Bergers and Sierras is that they will not fit in a AR15 magazine. They are long range bullets and are too long to seat properly into a AR15 mag. But I have heard that some people can get a 77gr SMK to cycle a subsonic round. But no word on the load or what special modifications if any are needed to make it run.

 

[SIG_Fiend]

That's what I thought, just wasn't sure if they could be seated deep enough to barely work.

 

[txgunner00]

That's me in the first vid. I started loading sub-sonics for novelty more than anything else. I had the opportunity to use them in the field quite a bit last winter and I bet you would be surprised at how effective they are. I've taken many small animals (coons, foxes), several hogs and 2 deer (legally- ie. daylight, no can) with them. I once got 5 coons at one tank without spooking the group.

I had custom 75 grain bullets made that would partially expand/ fracture at sub-sonic velocities and they seemed to work as intended. One of the deer I took was facing me pretty much straight on. The point of impact was on the leading edge of it's left front shoulder and I recovered the back half of the bullet in the right hind quarter. I've never tried taking a deer with a .22 but I find it highly unlikely that one would get the same penetration as this did.

The loads I was shooting in the vid are 70g speer soft points w/ 5.5g of trail boss. I've only used these for plinking but I intend to use them on small game/ vermin this winter.