Talk to me about .300 blackout...

[P89]

A recent mix up on a vendors end provided me with a .300BLK upper. After a few attempts of contacting the vendor and waiting forever I finally got through. Instead of going through even more hoops to ship it back I just said I'll keep it, since I have enough lowers kicking around anyway, and what can you do for me on price on the original order. They did good on offering me a deep discount and shipping it right out even though the website said out of stock.

So now it looks like I'm into a new caliber that I know little about other than don't mix up your ammo with 5.56...that's bad.
Anyone shooting .300? Any advice/tips? How should I build it out? SBR & suppressed since it sub-sonic?

[pennlineman]

From a power perspective I'm not really impressed. With subsonic loads they are very quiet suppressed, this is where they shine IMO. I have a spare upper in 300 for my SBR, I'll probably end up getting a suppressor for it at some point.

[P89]

I'm not into designer AR's like colors, print and things of the sort but I'm thinking this may end up a "color" build with matching mags.
Just because some preliminary research revealed this picture.

[ExFlyinguy]

300blk in a nutshell- very similar in performance with 7.62x39 at supersonic speed.

I used to buy into the subsonic argument, but at sub-sonic speeds is it really any better than a 9mm or 45acp? I don't know - it makes a smaller hole, and aside from Lehigh defense making very expensive bullets for subsonic use, mostly what I have are round nose.

Was very expensive but I reload my own and cut 223/556 brass so I have no idea what today's prices are like.

I have a AR pistol w/ 10.5 barrel and a Ruger American Ranch bolt in .300 I use the Ruger as my deer rifle but haven't shot anything with it.

[daschnoz]

From a ballistics standpoint, super sonic loads are on par with 7.62x39mm (125gr class pill at about 2300-2400fps). The bonus is that you can use standard AR mags and the only difference is the barrel. The bad thing is that you can use standard AR mags and accidentally chamber 300BLK in a 5.56 chamber - and you get the above result.

[P89]

This thing is only 7" so it screams SBR suppressed.

Imagine my surprise...I was expecting a 18" rifle and when I open the box, ta-da!

[pennlineman]

This thing is only 7" so it screams SBR suppressed.

Imagine my surprise...I was expecting a 18" rifle and when I open the box, ta-da!

It does.

[P89]

It does.

Further research makes it seem like the popular thing to do with these.
Guess I'll get the paperwork ball rolling.

[NathanB]

They lose very little velocity from short barrels to full carbine length barrels. Where a 223 loses hundreds of FPS shortening to a 10.5 barrel. The 300blk loses like 40. It excels sbr and suppressed subsonic.

[notenoughguns]

I'm not into designer AR's like colors, print and things of the sort but I'm thinking this may end up a "color" build with matching mags.
Just because some preliminary research revealed this picture.

I have to agree with you there , I guess a color scheme is in order . Thanks for posting that picture !