300 Blackout

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fleabaggins

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Sorry if I missed this in any other posts....... I have recently become intrigued with the 300 Blackout. To fire it in my AR, is the only change needed a 300 Blackout barrel? In other words, would I use the same gas port, gas tube, bolt, bolt carrier etc as my 5.56 AR uses?
I could buy a complete upper, but it would be a heck of a lot cheaper if all I had to buy was a barrel.
Thanks, and Merry Christmas to all!


Thanks for all the replies. If I understand this correctly - 1) if I use a barrel with a carbine length gas tube, will it cause feeding/ejection/cycling issues? Or just a drop in power behind the bullet
2) I notice the pic on SFRC shows a 7.5 and 12.5" barrel, with the gas port at the same spot on both barrels (ie pistol length), but Canada Ammo shows 2 different gas port positions on their barrels, plus a 16" barrel with a carbine gas tube. Is that just an editorial issue? Do all 300 Blackout barrels come with a pistol length gas port, regardless of barrel length?
 
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Yeah, pretty much. The gas tube may vary depending on what barrel length you go with. Hope ya reload 'cause factory ammo ain't cheap to shoot. :p
 
you will need to run a pistol gas system.
i think all reputable manufactures come in pistil gas system only
regardless of barrel length.

remember cartridge was designed for 9 inch barrel.
 
Fleabaggins, if you only have the one 223 upper, I wouldn't bother converting it to a 300BLK upper as your only AR upper. Unless you got deep pockets, 300BLK is just too expensive to shoot a lot, not when you can shoot 223 for a lot less. If this is a second/third upper, fill yer boots. :)

Greenhorse six said:
At the most , a new barrel , gas tube , gas block , muzzle break or flash hider and maybe a hand guard .
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Why a new gas block? If the OP is swapping out an existing barrel and his current barrel is the same profile as the 300BLK one, he shouldn't need a new one. The old handguard should work if it's a freefloating one.

rdavidson said:
you will need to run a pistol gas system.
i think all reputable manufactures come in pistil gas system only
regardless of barrel length.

remember cartridge was designed for 9 inch barrel.
Click to expand...

Not always the case. Some 16" barrels come with carbine length.
 
Trinimon said:
Why a new gas block? If the OP is swapping out an existing barrel and his current barrel is the same profile as the 300BLK one, he shouldn't need a new one. The old handguard should work if it's a freefloating one.
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Because , if you want to try another caliber for your AR you're going to build another upper , that's the nature of the beast .
If you give a mouse a cookie , he'll want another .
 
To convert your AR platform you will have best results with a pistol length gas system.
To answer your original question you will need a barrel, a pistol length gas tube and a 30 cal muzzle device of your choosing. Other than that everything else from your 223 upper can be used.
As was already mentioned you will want to be handloading for it for best performance and the least impact on your bank account as factory loads are expensive compared to 223.
The 300BLK is a great cartridge and the comment above saying it's pointless without a supressor is total baloney. Granted it would be more fun suppressed but when running 110gr-130gr loads think of it like a more accurate 7.62x39 and in a nice rifle that the cartridge was designed to run in. When running 130-165gr supersonic it rings the gongs with authority and is really fun. Running 150-220gr subsonic would be better suppressed but it's still quieter and is a lot of fun. My 155gr supersonic A-max load will shoot sub moa in two of my rifles and sub 2 moa in my third rifle (I'm sure it would do better in that rifle with a little load development).

I wouldn't have a 300BLK AR if it was my only AR but if this is your second or third AR or upper I strongly recommend giving it a shot. It's accurate, feeds perfectly from an AR mag (including Beowulf mags), it's not expensive and is fun to load for, hits harder than a 223 when you're ringing gongs, and is capable of shooting every weight of 30 cal projectile you can get your hands on.

Keep in mind though that it mostly uses magnum pistol powders and not rifle powders so don't go into it thinking you're going to use the same powder you use in your 308. Read up on the cartridge velocities with different projectiles as well, some people get into 300BLK thinking it's a 308win in a small package and are then disappointed when they find out it's not what they thought it was.

Good luck and be sure to post pics if you buy or build one :)
 
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fleabaggins said:
Sorry if I missed this in any other posts....... I have recently become intrigued with the 300 Blackout. To fire it in my AR, is the only change needed a 300 Blackout barrel? In other words, would I use the same gas port, gas tube, bolt, bolt carrier etc as my 5.56 AR uses?
I could buy a complete upper, but it would be a heck of a lot cheaper if all I had to buy was a barrel.
Thanks, and Merry Christmas to all!
Click to expand...
Identical barrel length will utilize ALL of your current hardware. IMO I would purchase another upper and share the bolt Carrier group so you can switch back. If you dedicate your shooting to just the 300 you'll find that it becomes very very expensive to shoot. Play with it and use the 5.56 for serious shooting.
 
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I have to echo the others who chimed in already about the pistol length gas system. When I was sourcing my Blackout barrel years ago, every manufacturer I spoke to recommended a pistol length tube. My existing gas block and everything else worked fine. Will it still run with a longer gas system? For sure; you just might get reduced performance, depending on the gun. You may not notice anything, though, so it's up to you. A shorter gas tube isn't too expensive, especially when you're already shelling out hundreds on a new barrel and muzzle device. In any case, it's a fun round, and if you reload and don't mind making your own brass, it can become a lot more economical than buying factory. As with anything AR, the Blackout can get addictive. Be warned, my friend...
 
+1 for all the pistol gas system as others have suggested

i will add however that building a dedicated upper is the way to go and if you do i would highly recommend a dedicated new bolt (if not an entire carrier) and reason for that is in AR platforms the barrel and bolt wear together (into each other). As such if you are getting a new barrel, you can definitely use your existing bolt for 556 but given the cost and benefits, new barrel + bolt will make noticeable difference (depending round count of existing bolt). take it for what its worth.

last but not least, to at least one comment i read - reason for 300 BLK? this guy explains is much better than i ever could:

 
I just shot my 300 blk MK18 with subsonic 220 grain with a Dentler muzzle device and it was great. I would say near hearing protection safe IF I was outdoors.
 
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