300 BLK in AR

[IdahoElk]

Sorry if this is a stupid question, tried searching but need to get a definitive answer from you guys here.

Question: I have a 5.56 AR and would like to shoot 300BLK, Besides a new upper, what else do I need to do?
Thanks for any info.

 

[Hnthrdr]

You are correct, that is it. 5.56 lower and a .300 blk upper and you are in business

 

[4090Sharps]

Consider marking your magazines to distinguish between calibers so you don’t have an oopsie.

You can swap your bolt carrier group between the two if you want to save ~$100.

 

[Hnthrdr]

Consider marking your magazines to distinguish between calibers so you don’t have an oopsie.

You can swap your bolt carrier group between the two if you want to save ~$100.

Yes especially this! Because you put a .300 blk down your 5.56 upper and it is an expensive mistake

 

[Reburn]

I had a question about a 300 BLK as well.
What bullet yeilds the best kills when shot at subsonic speeds.
@Formidilosus

 

[4090Sharps]

Yes especially this! Because you put a .300 blk down your 5.56 upper and it is an expensive mistake

Here’s the example I was thinking of. Just stumbled across it again this morning.

Scary Stuff — .300 Blackout Fired in a .223 Rem Barrel « Daily Bulletin

Photos and Facebook post by Tactical Rifle Shooters Yet another .300 Blackout disaster. Unfortunately, that .300 Blackout cartridge can fit in a .223 Rem chamber. Shooting a .308-caliber bullet in .223 bore is a recipe for disaster. <img src=https://accurateshooter.net/pix/blk3002.jpg alt=.

bulletin.accurateshooter.com

 

[KHNC]

I had a question about a 300 BLK as well.
What bullet yeilds the best kills when shot at subsonic speeds.
@Formidilosus

Hornady Subsonic Ammo 300 AAC Blackout 190 Grain Sub-X FTX Box of 20

Hornady 300 Blackout Subsonic Ammunition is designed for accuracy and performance below the speed of sound. The 190 grain Sub-X (Subsonic - eXpanding)...

www.midwayusa.com

This is what you want if you choose to do it. I have had a lot of success with these at less than 100yds.

 

[justinspicher]

What does the 300blkout do that your 556 doesn’t? Serious question, I am genuinely curious.

 

[Duh]

What does the 300blkout do that your 556 doesn’t? Serious question, I am genuinely curious.

Shoot super quiet suppressed. Grand Thumb has a sweet video of what different rounds down range sounds like. It’s pretty scary what a subsonic 300 BLK sounds like 100 yards away.

 

[justinspicher]

I understand how quiet it can be, I use them for work. Not impressed with it enough to make that my primary reason.

 

[Hnthrdr]

What does the 300blkout do that your 556 doesn’t? Serious question, I am genuinely curious.

It’s a big heavy round going pretty slow, the attraction is really how quiet it can be when shot suppressed. I have one in a pistol AR… but really it would be kind of cool for a back east Midwest guy that is only going to shoot 150 yards

 

[boardwalk72]

I had a question about a 300 BLK as well.
What bullet yeilds the best kills when shot at subsonic speeds.
@Formidilosus

Maker bullets are pretty impressive at subsonic speeds.

 

[RobertLosekamp]

It’s a big heavy round going pretty slow, the attraction is really how quiet it can be when shot suppressed. I have one in a pistol AR… but really it would be kind of cool for a back east Midwest guy that is only going to shoot 150 yards

This is my thinking with my budget Hobbit rifle. I'm in southeast Indiana where shots are generally under 75 yards. Using 110 Barnes at 2300fps should do great for my use case.

 

[duffman]

I had a question about a 300 BLK as well.
What bullet yeilds the best kills when shot at subsonic speeds.
@Formidilosus

Discreet Ballistics has a subsonic expander. Lehigh has some interesting options but I’ve never tried them.

 

[Osteodoc08]

I love the 300 BLK. Where it shines is in 2 areas.
1. Barrel length being the same, it will have more energy than 223/556. Short barrels are cool and easy to move around. Think supers with 110-125gr fodder.
2. Subsonic

My personal fave is a Sig AR "pistol" ive added a larger 12" handguard to an 8" barrel with my Saker 762 screwed on (under the handguard) using 125gr NBT Supers for hunting under 150 yards which is most of my hunting locally for deer and pigs. Velocity is 2100 at the barrel.

I also love shooting 220's subsonic through it using CFE BLK at about 800 FPS. Soft recoil, the kids can shoot it and its just cool.

 

[justinspicher]

When you guys are using a 300blkout for hunting, are you dialing or holding for shots over 200yds? How often do you shoot that far?

 

[duffman]

When you guys are using a 300blkout for hunting, are you dialing or holding for shots over 200yds? How often do you shoot that far?

I’ve yet to take a shot over 200 with 300Blk. I usually take it when I’ll be taking shorter shots, hold for subsonics since it’s within 100 yards. I personally would dial past 200 with supers if I had the time. Less for me to screw up in the moment.

 

[Osteodoc08]

I'm sighted in at 100 yards. If a deer I hold at the top of the back if 200 yards. But thats a rare shot for me. I wouldnt shoot it at game more than 200 yards.

 

[Anschutz]

When you guys are using a 300blkout for hunting, are you dialing or holding for shots over 200yds? How often do you shoot that far?

I personally wouldn't. Use case for a .300blk for me would be going into thick woods where I know shots are short. If I expect longer shots, there are better choices for the AR platform. .223, 6ARC, or 6.5 Grendel would be my choices for the longer shots. If I did want to shoot over 200, I'd likely dial it.

Sent from my SM-S918U using Tapatalk

 

[SquatchHunter]

When you guys are using a 300blkout for hunting, are you dialing or holding for shots over 200yds? How often do you shoot that far?

I limited my hunting range with it to 125 yards and under. . I have a 9” SBR and the velocity just isn’t there for good expansion. I think a 16” barrel with 110gr drops below 1800fps (or right around) at 200. Where I use it, shots are 100 yards max.