Does it make sense for me to build a 300 blackout AR?

[Flymph]

5.56 has thicker brass, so they use a faster burning powder to compensate.

Thank you for clarifying.

 

[Flymph]

Maybe I over reacted... lol
(Glad I didn't use the bold font...)

 

[james2562]

A while back I upgraded my 308 to a subsonic & suppressed platform. While it was and is a fun project I have come to think its practicality is limited. One, subsonic rounds are slow and drop faster so their range is greatly reduced. Two, the low bullet weight plus the low velocity yields low power. A standard 308 win is 2,700 ft/#, a 223 is 1,300 ft/#, a subsonic 30 cal (308 or 300 bk) is 591 ft/#. To take deer you should be using 1,000 or greater ft/#.

ShootersCalculator.com | Bullet Energy Calculator

If you are seriously thinking about subsonic and suppressed fun look into the 458 SOCOM. if you have a 223 rig you would only need to change out the upper.

I would suggest you start out with a good lower assembly, get an upper to familiarize your self with the ar platform, then upgrade to what ever caliber you like later.

 

[Will_White]

A while back I upgraded my 308 to a subsonic & suppressed platform. While it was and is a fun project I have come to think its practicality is limited. One, subsonic rounds are slow and drop faster so their range is greatly reduced. Two, the low bullet weight plus the low velocity yields low power. A standard 308 win is 2,700 ft/#, a 223 is 1,300 ft/#, a subsonic 30 cal (308 or 300 bk) is 591 ft/#. To take deer you should be using 1,000 or greater ft/#.

ShootersCalculator.com | Bullet Energy Calculator

If you are seriously thinking about subsonic and suppressed fun look into the 458 SOCOM. if you have a 223 rig you would only need to change out the upper.

I would suggest you start out with a good lower assembly, get an upper to familiarize your self with the ar platform, then upgrade to what ever caliber you like later.

I do want to build a .458 eventually but I would either need a much larger disposable income, or I would need space to reload. Combined with ammo expenses the reduced mag capacity killed it for me in the mean time. However, once I get set up to reload, 458 has the advantage that it can share bullets with 45-70, same with 6.5 grendel and .260 rem, and .300 BO and .308 although that's not really an advantage for me in this case given that .260 has similar terminal performance and better ballistics.

 

[Will_White]

Upper- <broken link removed>

BCG- 5.56 Bolt Carrier Group, Complete - Black Nitride

Charging Handle- <broken link removed>

Handguard- UTG PRO AR 17
Look good?

 

[Flopsweat]

Upper- <broken link removed>

BCG- 5.56 Bolt Carrier Group, Complete - Black Nitride

Charging Handle- <broken link removed>

Handguard- UTG PRO AR 17
Look good?

Going to need a low profile gas block?

 

[Boboclown]

Upper- <broken link removed>

BCG- 5.56 Bolt Carrier Group, Complete - Black Nitride

Charging Handle- <broken link removed>

Handguard- UTG PRO AR 17
Look good?

You'll need to get a low profile gas block to use that handguard. You're better off getting an upper that doesn't have a front sight on it.

 

[Flopsweat]

You'll need to get a low profile gas block to use that handguard. You're better off getting an upper that doesn't have a front sight on it.

Got you by .001 seconds.

 

[Flymph]

You'll also need a NWFA lower to go with that.

 

[Boboclown]

Got you by .001 seconds.

I was undecided on how to approach it. Whether to be a clown or be serious.

 

[Flopsweat]

I was undecided on how to approach it. Whether to be a clown or be serious.

Am I going to need to play Tears of a Clown for you now?

 

[Flymph]

You'll need to get a low profile gas block to use that handguard. You're better off getting an upper that doesn't have a front sight on it.

With a name like that, you should probably tell a joke, then disclaim it in a way that makes people unsure as to if you're joking or not.

 

[Will_White]

You'll need to get a low profile gas block to use that handguard. You're better off getting an upper that doesn't have a front sight on it.

Going to need a low profile gas block?

I'm planning on just trimming the sight down, looked at a few youtube videos and it seems pretty simple. I'm a welder/fabricator so I know my way around a grinder.

You'll also need a NWFA lower to go with that.

I already have a lower mostly built, just need a grip screw and the buffer retainer pin and spring because my LPK was missing them. Next year when I build a 6.5 grendel though I'll have to pick one up.

 

[Flymph]

Sounds good to me!

 

[Boboclown]

I'm planning on just trimming the sight down, looked at a few youtube videos and it seems pretty simple. I'm a welder/fabricator so I know my way around a grinder.

That poor front sight... Its easier to just use a low profile gas block instead, they sit lower and take less space with less effort. Also easier to fix if its canted. If a front sight block is canted, it means needing to redrill the barrel for the pins.

 

[Will_White]

That poor front sight... Its easier to just use a low profile gas block instead, they sit lower and take less space with less effort. Also easier to fix if its canted. If a front sight block is canted, it means needing to redrill the barrel for the pins.

I'm not sure why it would matter if it was easier to fix if it is canted? If I pull the pins out, shave it so it fits and put the pins back in the same holes it seems like it should end up in the same spot. If it is canted from the factory and it doesn't interfere with the rifles cycling it's going to be under the hand guard so it won't be visible and won't effect the sights. Unless I'm missing something? In any case if I totally screw it up I can still buy a low profile gas block to put in its place, and if I succeed I saved some money for ammo.

 

[Boboclown]

I'm not sure why it would matter if it was easier to fix if it is canted? If I pull the pins out, shave it so it fits and put the pins back in the same holes it seems like it should end up in the same spot. If it is canted from the factory and it doesn't interfere with the rifles cycling it's going to be under the hand guard so it won't be visible and won't effect the sights. Unless I'm missing something? In any case if I totally screw it up I can still buy a low profile gas block to put in its place, and if I succeed I saved some money for ammo.

Even if it doesn't affect cycling, it will still affect the gas tube. It will either wear out the gas key quicker or damage the gas tube. Won't be noticeable at first, but its what I noticed when I had a PSA upper and had to fix the cant. It showed noticeable wear on one side of the gas key while the other was virtually untouched.

 

[DirectDrive]

Upper- <broken link removed>

I don't like this choice for a build that needs a low-pro gas block.
Rifle gas was designed for 20"....this will have 2" less "dwell"
I would go for a mid-gassed 16" with a low-pro GB

BCG- 5.56 Bolt Carrier Group, Complete - Black Nitride

For less money and maybe a better BCG, I'd go with a ToolCraft
AR15 BCG (Bolt Carrier Group) - Monmouth USA
(or ToolCraft NiB for same money)

Charging Handle- <broken link removed>

I like the medium, Mod 4
Mod 3 would be good for a scoped rig

Handguard- UTG PRO AR 17

These guys (Leapers) have put out some junk in the past.
The Pro series is supposed to be better.
I would go to the Rainier Arms website (top notch shop) and have a look around.
I think for not much more $ you could find a better HG

My two cents
YMMV

 

[DirectDrive]

A historical post from the man himself....
.223 Wylde chamber and a little luck.

 

[Will_White]

What about this upper?
PSA 16" Mid-length Freedom Stainless Steel 1/7 Dissipator - Without BCG or CH - 43633
It has a mid-length low profile gas block under the hand guard so I could swap it out for a free-float, would the front site cause any issues?

Edit: other then having to remove it to put the rail on, and not using it as sling mount.