Is gas an issue on 300 Blackout AR's like 5.56?

Faktory 47

Leshaire

Weekend Warrior
Mar 27, 2015
3,343
1,994
113
Acworth
Zip code
30102
I might want to build a 300blackout to run my 30 cal can on. I know this probably sounds dumb, but does this round when suppressed typically have over gassed issues like shit in your face and carrier velocities that could be harmful to the gun?

It doesn't seem like nearly as many people are running as much adjustable gas type crap on these guns, like you see on 556 ARs.

TL;DR
My plan is to build a 7.5 - 9 inch suppressed AR in 300 blackout and run mostly subsonic ammo but would like to be able to shoot supersonic ammo as well. Should I look into controlling gas or nah?
 

SouthernSlammed

Gingerbeard Operator
Lifetime Supporter
Aug 29, 2015
3,107
2,616
113
Fapville
Zip code
31061
Sub'd!

I'm curious if you run the same lower for 300blk & 556, will 300blk operate well with the heavier buffer needed for suppressed 556!
 
  • Like
Reactions: Leshaire

Mac11FA

Disgruntled large member
Super Moderator
Lifetime Supporter
Patriot Lifetime
Mar 26, 2015
3,840
3,011
113
Locust Grove, GA
Zip code
30248
I do not have an SBR however I think that it will not be an issue as you will be running lower chamber pressures with subsonic rounds. Make sure you go with a length that will stabilize projectile as well as an adjustable gas block in case you have cycling issues.

Since bolt is same as 5.56 another thing to consider is an M16 bolt (full auto) as the added weight will help with lock time.

Of course as I initially stated, I have not built an SBR. I do have a standard length 300 blkout and have no gas issues when suppressing subsonic rounds.
 
  • Like
Reactions: Leshaire

Leshaire

Weekend Warrior
Mar 27, 2015
3,343
1,994
113
Acworth
Zip code
30102
I do not have an SBR however I think that it will not be an issue as you will be running lower chamber pressures with subsonic rounds. Make sure you go with a length that will stabilize projectile as well as an adjustable gas block in case you have cycling issues.

Since bolt is same as 5.56 another thing to consider is an M16 bolt (full auto) as the added weight will help with lock time.

Of course as I initially stated, I have not built an SBR. I do have a standard length 300 blkout and have no gas issues when suppressing subsonic rounds.
Do you have problems suppressing supersonic rounds? Increased carrier velocity and gas coming out towards your face?
 
  • Like
Reactions: Mac11FA

Leshaire

Weekend Warrior
Mar 27, 2015
3,343
1,994
113
Acworth
Zip code
30102
Sounds like a research project! In for the report or help with the research!
Haha im googling now. Have been for a few days but still. I dont think Im gonna get by as easy as on my 556. That gas port on that barrel is effing perfect! Surprisingly runs all ammo suppressed and not so far. Im not gonna be as lucky with 300 though since I wanna run subs and supers I think.
 

Mac11FA

Disgruntled large member
Super Moderator
Lifetime Supporter
Patriot Lifetime
Mar 26, 2015
3,840
3,011
113
Locust Grove, GA
Zip code
30248
Do you have problems suppressing supersonic rounds? Increased carrier velocity and gas coming out towards your face?
Unfortunately I cannot shoot supers at this time. I am awaiting my Sandman Ti for that. I will definitely test once I get it!
 
  • Like
Reactions: Leshaire

Leshaire

Weekend Warrior
Mar 27, 2015
3,343
1,994
113
Acworth
Zip code
30102
Unfortunately I cannot shoot supers at this time. I am awaiting my Sandman Ti for that. I will definitely test once I get it!
All good!

Im leaning towards the Gemtech adjustable bolt/carrier maybe since I really dont want to have to stress to get under the rail to the gas block thats 4 million effing degrees if I decide to change ammo. Or that WAR upper. Idk. Either is better than an adj gas block imo
 
  • Like
Reactions: Mac11FA

Mac11FA

Disgruntled large member
Super Moderator
Lifetime Supporter
Patriot Lifetime
Mar 26, 2015
3,840
3,011
113
Locust Grove, GA
Zip code
30248
All good!

Im leaning towards the Gemtech adjustable bolt/carrier maybe since I really dont want to have to stress to get under the rail to the gas block thats 4 million effing degrees if I decide to change ammo. Or that WAR upper. Idk. Either is better than an adj gas block imo
I would go with WAR upper.
 
  • Like
Reactions: Rwjeter

Leshaire

Weekend Warrior
Mar 27, 2015
3,343
1,994
113
Acworth
Zip code
30102
I would go with WAR upper.
Why is that? I looked pretty hard for actual real reviews the other day and couldnt find more than unboxing bullshit and like "Its so great ive shot it once!" type reviews. Im wondering how they hold up over time. If im gonna drop 250 on a stripped upper I want to make sure its worth a damn lol.
 
  • Like
Reactions: Rwjeter and Mac11FA

Mac11FA

Disgruntled large member
Super Moderator
Lifetime Supporter
Patriot Lifetime
Mar 26, 2015
3,840
3,011
113
Locust Grove, GA
Zip code
30248
Why is that? I looked pretty hard for actual real reviews the other day and couldnt find more than unboxing bullshit and like "Its so great ive shot it once!" type reviews. Im wondering how they hold up over time. If im gonna drop 250 on a stripped upper I want to make sure its worth a damn lol.
@Red Dawn has one on one of his builds. I cannot remember which, but he loves it!
 
  • Like
Reactions: Rwjeter