300 subsonic ranging

[Rich 10mm]

Just got done my 300 BLK project. Trying to sight it in. The Red Dot is 1.5" above bore. What is the best zero to use? I'll be using subsonic ammonia primarily for personal/home defense.

 

[Theohazard]

For home defense, I'd probably recommend a 25 yard zero. But I'd also strongly recommend against using subsonic ammo for home defense with a 300 Blackout.

Subsonic ammo will be much less effective and will penetrate walls a lot more than supersonic ammo. When paired with a silencer, subsonic ammo is great when you're shooting for fun or you're hunting and you need the shot to be as quiet as possible. But for home defense use, a silencer will prevent you from getting noticeable hearing loss even when using supersonic ammo; the purpose of a silencer for home defense isn't to be as quiet as possible, but it's just to lower the noise to a tolerable level. And a silencer combined with supersonic ammo will do that.

 

[Pushrod]

To add to Theohazards post, the suppressor will also knock down the flash of the shot appreciably so you aren't blinded.
Although subsonic ammo is 'less' effective than supersonic, in cqb situations it is still effective.

 

[Rich 10mm]

I just feel that a heavier bullet moving at slower speeds will have more knockdown power. Also I don't have the money to enter the ranks of the NFA equipment and tax stamps. I actually looked at a ballistics chart and ended up sighting it in with a 10/100 yard zero. Only a 3" deviation at 50 yards. Way more than I would be using in the house anyway. Subs also have a quicker follow up shot.

 

[Theohazard]

I just feel that a heavier bullet moving at slower speeds will have more knockdown power.

It's just the opposite. The subsonic ammo will be far less effective on target than supersonic ammo. Significantly so.

There's no such thing as "knockdown power". Bullets don't knock people down. And a subsonic 300 Blackout has about the same muzzle energy as a .45 ACP, whereas supersonic 300 Blackout loads are intermediate-powered rifle rounds, which are far more powerful and effective than any defensive handgun round.

For home defense, I'd recommend a 110 gr. ballistic tipped-hollow point supersonic load.

 

[Theohazard]

But if you're not planning on using a short barrel or a silencer, I'd recommend a 5.56 over a 300 Blackout. In my opinion, if you're using a non-NFA rifle, 5.56 is probably the best home defense round out there.

Keep the 300 upper for hunting and use the 5.56 for plinking and home defense.

 

[Rich 10mm]

I'm worried about over penetration with the supersonics.

 

[Goosey]

I just feel that a heavier bullet moving at slower speeds will have more knockdown power.

These are the effects of the Remington 220-grain subsonics versus 10% ballistic gelatin.

And for comparison, this is the (supersonic) 110-gr Barnes TAC-TX.

 

[gojuice101]

I've noticed the same thing testing my bullet traps. Heavy, slow moving bullets penetrate much farther and don't disperse much energy. Light, fast moving rounds don't penetrate near as far and disperse their energy much better.

I know its not the same as ballistics gel, but similar results in a different medium.

 

[Theohazard]

I'm worried about over penetration with the supersonics.

If you're worried about over-penetration, then you should be using supersonic ammo. Like others pointed out, subsonic rounds will penetrate farther than supersonic rounds. And they'll do far less damage along the way. The videos Goosey linked show how dramatic the difference is.

 

[Rich 10mm]

Thanks goosey. Those vids where helpful and enlightening. Thinking about a laser for subs and using my green dot for supers. Best of both worlds in one package!

 

[Theohazard]

Thinking about a laser for subs and using my green dot for supers. Best of both worlds in one package!

You said you're not interested in getting a silencer, so why bother shooting subs at all? Subsonic ammo has inferior performance in every way compared to supers, the only advantage is that it's super-quiet with a silencer.

 

[jmorris]

If your worried about over penetration run a shot gun with something between bird and buck shot. I am no expert though, never have fired a shot in SD inside my home or out in all my years, knock on wood it stays that way. My NFA toys stay locked up so if I ever did my ears might ring a bit but thats no different than my CCW's, none of them are suppressed.

 

[Theohazard]

If your worried about over penetration run a shot gun with something between bird and buck shot.

If you're worried about over-penetration the best home defense round is a .223/5.56 loaded with hollow- or soft-points.

 

[redbullitt]

My house gun is a SBR with a short suppressor. Here is my take.

I like the Barnes 110 bullets or the Nosler 125s at or above 2k FPS. Performance on deer with both bullets has been very good and I would think they would do well on 2 legged goblins.

My rifle right now just has irons on it and I am sighted in for 25 yard zero. With a red dot I might do it a little further out, but since its a house gun 25 is plenty for me.

I do not use the subsonic ammunition unless I want to be quiet. They kill animals fine, but there is a good deal less trauma AND you have to hit CNS for a fast kill. Even heart shots will give you a chase... less damage than using a bow. Unless you spring for the good subsonic projectiles from lehigh or something like that stick with super sonic. It will kill whatever you shoot much more effectively.

 

[Woolecox]

It’s the BULLET

There is some good and some bad information in this post. If you are using the correct bullet (projectile) for the task at hand, you will NOT get over penetration with EITHER sub or supersonic ammunition.

It completely depends on the bullet you are using and what it was designed to do. Penetration, or maximum expansion.

I seems that some people assume that when we use the 300 BLK for home defense with sub sonic ammo, we are always using something like a 220 grain Match King. Not the case.

There are much better choices for HD were the 300 BLK is concerned. The excellent Lehigh Defense 194 grain Max Expansion bullet is one of them. And yes, it produces more energy, than a 45 ACP, higher BC’s, higher sectional density, etc. Also, hand someone a 1911 and a carbine and see who put more rounds on target faster, in any situation.

I reload, so cost is reduced but, these bullets are expensive. I will use bulk Match King bullets for practice and load up some of the Max Expansion for Home D. The ballistics are close enough inside 150 yards to not matter.

There are so many advantages to suppressed SBR’s when using subsonic ammo that there is not enough space here to discuss it all. The downside is cost. As far as supersonic ammo for home defense is concerned, there are bullets made for that too. They will also expand and do not over penetrate.

Carefully watch the video below. There are many others on Lehigh’s website that debunk all the myths.

https://youtu.be/sgcGLi5v67s

Other Videos

My go-to Home Defense weapon; a Sig MPX SBR suppressed in 9mm. I shoot 147 grain XTP’s at a 1080 fps. Also in the works for a SBR 300 BLK.

 

[Rich 10mm]

Thanks wool! I'm gonna go with a subsonic 194 grain max expansion.

 

[Theohazard]

There is some good and some bad information in this post. If you are using the correct bullet (projectile) for the task at hand, you will NOT get over penetration with EITHER sub or supersonic ammunition.

It completely depends on the bullet you are using and what it was designed to do. Penetration, or maximum expansion.

No, it's not correct that it completely depends on the bullet you're using. It's not just about the bullet, it's also about the bullet's velocity. Lighter-weight ballistic-tipped hollow-point supersonic loads expand and fragment for two reasons: 1) bullet construction, and 2) bullet velocity. At lower velocities, there's often not enough energy for the bullet to reliably fragment, and therefore it tends to penetrate more and cause less damage to the target. Sure, there are subsonic bullets that are designed to expand at subsonic velocities, but they still don't cause as much damage as their supersonic counterparts.

I seems that some people assume that when we use the 300 BLK for home defense with sub sonic ammo, we are always using something like a 220 grain Match King. Not the case.

There are much better choices for HD were the 300 BLK is concerned. The excellent Lehigh Defense 194 grain Max Expansion bullet is one of them. And yes, it produces more energy, than a 45 ACP, higher BC’s, higher sectional density, etc. Also, hand someone a 1911 and a carbine and see who put more rounds on target faster, in any situation.

Sure, that Lehigh Defense load probably works well, but a supersonic defensive load will work even better.

There are so many advantages to suppressed SBR’s when using subsonic ammo that there is not enough space here to discuss it all.

But he's not using a silencer. Therefore, why use subsonic ammo when supersonic ammo performs better in every single way?

 

[Theohazard]

Thanks wool! I'm gonna go with a subsonic 194 grain max expansion.

Woolecox gave you some bad information. That 194 gr. max expansion subsonic load will be worse in every single way than a 110 gr. ballistic-tipped hollow-point supersonic load. Your subsonic load will cause less damage on target and will penetrate walls more if you miss.

I find it confusing that you came to this forum asking advice, you received lots of good advice from myself and others (along with evidence showing why that advice was correct), and then Woolecox comes along with some bad information and you decide to listen to him?

Go ahead and use subsonic ammo if you want to, just know that it will perform worse than supersonic ammo both in terms of over-penetration and in terminal performance. The whole purpose of subsonic ammo is to be super-quiet with a silencer. Without a silencer it's pointless and much less effective.