Lightest subsonic bullet for 7.5” suppressed .300 Blackout

[Pokem807]

Title says it all. I have a Dead Air Primal in jail and have decided to put together a HD .300 Blackout. It will be suppressed 100% of the time. Given the current state of ammo cost and availability, I’m just looking to give myself the most options.

This will be my first time messing with this caliber, so any other advice on my build would also be appreciated.

 

[swampratt]

Is this supposed to be a semi auto build that needs to cycle?
If it is a bolt or single shot I will say this I run a Lee 311-100-2R cast and powder coated in a bolt .308
at 664 FPS and stupid accurate.
Why 664 fps.
Because with that particular powder (Red Dot) and that velocity I do not need to resize my cases.

Perfect for back yard critter killing.

You would shoot those all day and laugh every time you pulled the trigger.
No recoil and hitting the wood target is louder than the gun report which is just about Nill.

I see no reason that tiny cast would not work.

 

[Profreedomokie]

I have a 300 Whisper I built about 20 years ago for subsonics. Like swampratt mentioned its a big difference on how to load if you're using a semiautomatic rifle. My AR is using a 9mm recoil spring with a buffer weight that is empty. It is set up this way to function with bullets as light as 165 grains. You may have to pick the bullet weight and style you want and keep playing with the powder charge until you get a load that will function 100% of the time. To be really quiet stay around 1050 fps. When I shoot mine all I hear is the spring. I have no idea on what factory ammo on the shelf may work for you. Reloading would be your best bet.

 

[Pokem807]

Is this supposed to be a semi auto build that needs to cycle?
If it is a bolt or single shot I will say this I run a Lee 311-100-2R cast and powder coated in a bolt .308
at 664 FPS and stupid accurate.
Why 664 fps.
Because with that particular powder (Red Dot) and that velocity I do not need to resize my cases.

Perfect for back yard critter killing.

You would shoot those all day and laugh every time you pulled the trigger.
No recoil and hitting the wood target is louder than the gun report which is just about Nill.

I see no reason that tiny cast would not work.

Whoops. Guess I should have mentioned that I’ll be picking up a .300 BO upper and only running factory ammo. Not planning on using it for hunting or plinking, but that may change once I put some rounds through it. I’ll probably set it up to run with a red dot and NODS, and may occasionally use it to dispatch a coon or other varmint checking out my chicken coop.

 

[Profreedomokie]

I can't help at all then. I've always loaded my own ammo.

 

[mr ed]

Shoot'em at a target first to make sure they don't tumble. Hate to see you have a baffle strike.

 

[adamsredlines]

Subs and lightweight bullets make for a pretty anemic HD round...and will not be cheap since you're getting into oddball territory for the caliber.
And that's just talking energy and cost, not even taking into account those light weight bullets likely won't expand at subsonic velocities.

 

[crapsguy]

Title says it all. I have a Dead Air Primal in jail and have decided to put together a HD .300 Blackout. It will be suppressed 100% of the time. Given the current state of ammo cost and availability, I’m just looking to give myself the most options.

This will be my first time messing with this caliber, so any other advice on my build would also be appreciated.

I got an 300blk ar a while back and found that I needed pretty heavy bullets to cycle it - and they need to have a profile similar to 223 to feed from the mag dependably -- I load my own and finally ended up getting a 230gn bullet made for 300blk they work/cycle very well -- since then I have been working away from subsonic using a 160gn SP bullet that is working and cycling except sometimes it doesn't lock back on the last round +++ still work in progress

 

[Pokem807]

Subs and lightweight bullets make for a pretty anemic HD round...and will not be cheap since you're getting into oddball territory for the caliber.
And that's just talking energy and cost, not even taking into account those light weight bullets likely won't expand at subsonic velocities.

I have a lot of .45ACP stacked. Have given thought to just running a PCC or AR upper in that caliber instead.

 

[Glocktogo]

For HD work, something in the 110-120gr range at 2,000 fps + is your best bet. If you have concerns regarding overpenetration then the Hornady 110gr V-Max would be a good choice. It also tends to be one of the cheaper offerings with a performance bullet designed for 300BLK.

If you're wanting a barrier blind round that works well for HD and general use, look for any of the offerings using the 110gr or 120gr Barnes solid copper bullet (Barnes sells a regular 120gr JHP and it's not the same). I'm using the Sig Sauer Elite (SGE300H1) that uses the non-tipped Barnes solid copper 120gr bullet, rated at 2,250 fps. It's designed for SBR's and works well out of my 7.5" 300.

Subs will obviously be the quietest in your can, but supers are definitely superior for defense uses.