sub sonic?

[Tikkamike]

I have a question about sub sonic rounds.. I have never done much reading on this so excuse my ignorance. What is the purpose of these low velocity rounds like the 300 whisper, 300 blk out? I realize its low velocity to achieve sub sonic speed BUT why not load a 308 down with a super heavy bullet? My only possible theory is you are loading those cartridges designed for low velocity at full pressure and its probably more efficient and consistent that way? someone help me out.

 

[bigsky23]

I do exactly that, I shoot Berger 210 vld's out to 500 yds subsonic with very good accuracy. There is no down side I can find. Let me know if you want my load info to use as a starting point.

 

[cohunt]

Twist rate needs to be sufficient for heavies-- most 308s are 1:12- 1:10 so that limits the weight a bit.
Subs in a 300bo will cycle the action on semi auto, most 308w semi autos wont cycle with subs.
Smaller case for 300bo so easier to load for it than 308w. Reload data is more readily available.
You could download a 300wm also

 

[bigsky23]

Twist rate needs to be sufficient for heavies-- most 308s are 1:12- 1:10 so that limits the weight a bit.
Subs in a 300bo will cycle the action on semi auto, most 308w semi autos wont cycle with subs.
Smaller case for 300bo so easier to load for it than 308w. Reload data is more readily available.
You could download a 300wm also

Correct, twist rate must be sufficient. I agree load data is very difficult to find, I developed my own for .308 win and .338 LM. The .338 is a blast to shoot suppressed, it's like shooting a 300 grain pellet gun.

 

[cohunt]

Correct, twist rate must be sufficient. I agree load data is very difficult to find, I developed my own for .308 win and .338 LM. The .338 is a blast to shoot suppressed, it's like shooting a 300 grain pellet gun.

oh yea, I ended up doing my own load data chart for my 308w--I ended up using pistol powder--super quiet but not always consistent due to the large case capacity with small amounts of powder-- some guys use dacron fill to keep the powder up against the primers--I'm not a dacron fan--that 338L sounds like fun, what weight were you able to stuff in there at sub speeds?

some guys cast their own short blunt nose soft lead bullets so they can run heavier pills but still stabilize them in std twist rates

 

[jdg300rum]

308 with sub loads is a blast. They are great to hunt with if you limit your shooting distance. Usually 100 yards and in. You have to remember it like shooting a bow behind the front leg shot placement. I use outlaw and maker bullets with great success. I do practice a lot. It's not forever one.

 

[bigsky23]

oh yea, I ended up doing my own load data chart for my 308w--I ended up using pistol powder--super quiet but not always consistent due to the large case capacity with small amounts of powder-- some guys use dacron fill to keep the powder up against the primers--I'm not a dacron fan--that 338L sounds like fun, what weight were you able to stuff in there at sub speeds?

some guys cast their own short blunt nose soft lead bullets so they can run heavier pills but still stabilize them in std twist rates

I am running 300gr SMK's with 21.5 gr of Trail Boss. Perfectly stable and just over 1000fps.

 

[TBuckus]

So it sounds to me the only significant difference is which platform you are putting it on, AR10 vs AR15. And twist rate.

 

[Tikkamike]

So it sounds to me the only significant difference is which platform you are putting it on, AR10 vs AR15. And twist rate.

It can be on a bolt gun or anything else too

 

[TBuckus]

It can be on a bolt gun or anything else too

Good point. I guess I just think AR platform when I hear 300BLK.

 

[Pete FARR]

I am running 300gr SMK's with 21.5 gr of Trail Boss. Perfectly stable and just over 1000fps.

What twist rate are you using?

 

[bigsky23]

1 in 10 and 1 in 8, both will stabilize the bullet well.

 

[hnts4fun]

How about bullet performance on game? Any favorite bullets for sub sonic hunting?

 

[cohunt]

How about bullet performance on game? Any favorite bullets for sub sonic hunting?

the 195 grain cavity back bullet does excellent on game for a subsonic expanding monolithic bullet