Suppressed Subsonic 300 Blackout

[shimatsuken]

Hi guys!

I'm looking at making a suppressed, subsonic only 300 Blackout. I want it to be reasonably quiet (if someone else is shooting, my shots are invisible) or whisper quiet while balancing good barrel length and can length. I don't see this gun being used past 50 yards, 75 is stretching it for what the gun's intended purpose is.

I was thinking a 5.5 inch barrel with a Surefire SOCOM300 SPS or something similar, full barrel length with can going to 14.5 inches max, aiming for 12 or so.

Has anyone got specifically decibel counts from down range as opposed to shooter's position with different lengths of barrel or cans? Any issues with dwell time, or is that a myth? I don't mind issues with sound at my position so long as down range is quieter.

Thanks for the help!

 

[strikeeagle1]

I don't mind issues with sound at my position so long as down range is quieter.

IF they hear the shot, you missed.

 

[BurtG]

Think 9 is the sweet spot. Could be mistaken. You want a full powder burn. Longer is most likely quietest

 

[rmfield]

Tried 8", but ended up with 9".

 

[Hoser]

I have a 10 inch and it is louder than my 16 inch with the same can. To my ears anyway. Might be different on a meter.

On gas guns I have settled on 9-10 inch barrels and 16 on bolt guns.

 

[shimatsuken]

Tried 8", but ended up with 9".

What drove that decision? Gas issues? What can did you use?

 

[shimatsuken]

I have a 10 inch and it is louder than my 16 inch with the same can. To my ears anyway. Might be different on a meter.

On gas guns I have settled on 9-10 inch barrels and 16 on bolt guns.

What can do you got on?

Nah, I've seen the same. More time for stuff to burn. Bolt 300s are quiet. I just want a stupid little plinker for a woods-y self defense thing that makes people go "ooooo" when I whip it out. Shoot cans at a campfire type thing.

 

[Capri_Man]

The real question is do your reload your own ammo, because not all powder is created equal. Some are just flat quieter than others. I went 10" because I wanted my suppers to have decent velocity. With that not being an issue for you go as short as the suppressor you intend to run will let you.

 

[shimatsuken]

The real question is do your reload your own ammo, because not all powder is created equal. Some are just flat quieter than others. I went 10" because I wanted my suppers to have decent velocity. With that not being an issue for you go as short as the suppressor you intend to run will let you.

To answer your question, I would not be for this gun. Just factory Ammo Inc STELTH ammo, 220 grain subs.

Is there really much of a difference from, say, a 5.5 to a 7.5 or up with something like the SOCOM 300?

 

[MO Fugga]

To answer your question, I would not be for this gun. Just factory Ammo Inc STELTH ammo, 220 grain subs.

Is there really much of a difference from, say, a 5.5 to a 7.5 or up with something like the SOCOM 300?

I have a 5.5 and a 7.5, and speed difference is around 150 to 250 fps depending on load. No can.

 

[Capri_Man]

To answer your question, I would not be for this gun. Just factory Ammo Inc STELTH ammo, 220 grain subs.

Is there really much of a difference from, say, a 5.5 to a 7.5 or up with something like the SOCOM 300?

That I don't know, but I don't think it would.

 

[Kickin45]

@shimatsuken
You need to learn how to use the search function and research.
Best thing you can do on this site is read and educate yourself.
Your posts so far sound very uneducated. Nothing wrong with that. That’s how every single one of us here started out.
But read. Then read some more. Don’t ask for ideas or opinions, cuz they’ll range from A-Z

Read so much that you can see a clear, proven choice by the majority on what’s used.
Based on your name and pic, I’m going to assume you’re pretty young. Nothing wrong with that, I wish I was still young lol
So as with any subject in school or college, the more you educate yourself, the better off you’ll be. Same with this.
Usually asking questions is a good way to learn. That’s not usually the case here unless you know the experience of the person answering.
Use the search.
Go to google, type snipers hide, and then your question. It’ll guide you to the most applicable answers.
Good luck, and be safe.

 

[TonyAngel]

If this is going to be a dedicated subsonic/suppressed setup, I'd go for something in the 8" range. This will leave you with enough rail space to mount a light or other accessory.

With subsonic ammo, barrel length vs velocity isn't much of an issue. There isn't much difference in velocity between a 7" and a 16" barrel with subsonic ammo.

Think 9 is the sweet spot. Could be mistaken. You want a full powder burn. Longer is most likely quietest

This barrel length getting you a "full powder burn" is a myth. With super sonic ammo, there are appreciable velocity gains up to 16".

 

[TonyAngel]

I should have added that I have a 5" AR in 9mm that is a dedicated suppressor host. With a 6" suppressor direct threaded to the barrel, it is a very handy package, BUT not very comfortable to shoot with a handguard typical of that barrel length. I wound up having to tuck the suppressor under a longer handguard to get any sort of usable rail length.

Tucking the suppressor comes with its own issues, the big ones being heat and choice of mount.

 

[BurtG]

@shimatsuken
You need to learn how to use the search function and research.
Best thing you can do on this site is read and educate yourself.
Your posts so far sound very uneducated. Nothing wrong with that. That’s how every single one of us here started out.
But read. Then read some more. Don’t ask for ideas or opinions, cuz they’ll range from A-Z

Read so much that you can see a clear, proven choice by the majority on what’s used.
Based on your name and pic, I’m going to assume you’re pretty young. Nothing wrong with that, I wish I was still young lol
So as with any subject in school or college, the more you educate yourself, the better off you’ll be. Same with this.
Usually asking questions is a good way to learn. That’s not usually the case here unless you know the experience of the person answering.
Use the search.
Go to google, type snipers hide, and then your question. It’ll guide you to the most applicable answers.
Good luck, and be safe.

Good way to get dead forums

 

[shimatsuken]

I should have added that I have a 5" AR in 9mm that is a dedicated suppressor host. With a 6" suppressor direct threaded to the barrel, it is a very handy package, BUT not very comfortable to shoot with a handguard typical of that barrel length. I wound up having to tuck the suppressor under a longer handguard to get any sort of usable rail length.

Tucking the suppressor comes with its own issues, the big ones being heat and choice of mount.

I was actually looking into suppressing an 8 inch MPX, but was unsure which would be quieter. I've been looking online and asking people that have similar setups but no one has a clear answer (which is why I thought to pose the question myself).

Since my goal is to be quiet and not really go to 50 yards and beyond, I guess my question for you is how quiet is your subsonic 9mm compared to your subsonic 300 Black?

Some people tell me 300 Black is comparable to a subsonic 22, other people tell me since 9mm has less powder it's by definition quieter.

 

[MadDuner]

I was actually looking into suppressing an 8 inch MPX, but was unsure which would be quieter. I've been looking online and asking people that have similar setups but no one has a clear answer (which is why I thought to pose the question myself).

Since my goal is to be quiet and not really go to 50 yards and beyond, I guess my question for you is how quiet is your subsonic 9mm compared to your subsonic 300 Black?

Some people tell me 300 Black is comparable to a subsonic 22, other people tell me since 9mm has less powder it's by definition quieter.

My 9mm suppressed with subs is WAY quieter than my 300BO.
Like pellet gun sound vs cap gun sound.
Down range it still only sounds like PewPew.
Both are good to 100 yds without acting like a mortar shot.

 

[shimatsuken]

My 9mm suppressed with subs is WAY quieter than my 300BO.
Like pellet gun sound vs cap gun sound.
Down range it still only sounds like PewPew.
Both are good to 100 yds without acting like a mortar shot.

What are your specs??? What can do you run and how long is your setup? What grain do you run?

Any issues suppressing a short stroke piston like the MPX compared to a direct impingement?

Tangential question I also cannot find answers to online: Do hollow points cause issues in cans or PCCs? Or am I stuck running ball ammo?