Bloodline 8.2″ 300 Blackout Barrel

From: $170.00

This Rosco 8.2” 300 Blackout Bloodline Barrel was designed for SBR and Pistol use in conjunction with suppressors. This is the shortest that we will go to allow you the flexibility of a shorter Personal Defense Weapon (PDW) without sacrificing performance or ballistics. ALL NFA RULES APPLY!

(7 customer reviews)

Melonite Gas Tubes

Our Rosco Melonite Gas Tubes have an extremely durable Black Nitride finish that increases corrosion resistance, wear resistance, fatigue strength and cosmetic appeal. These gas tubes work great under a handguard because they are more durable than standard gas tubes. Available in pistol, carbine, patrol length, mid-length, and rifle lengths. Does not include a roll pin.

Non-Adjustable Gas Block, v2

Our v2 Non-Adjustable Gas Blocks feature the same 'Bloodline' dependability, with improvements for the modern shooter.  We added a knockout hole at the front of the gas block to aide in removing the gas tube. Also featuring improved tolerances and finishes, making the v2 Gas Block a staple for years to come.

Adjustable Gas Block

Our Rosco Adjustable Gas Block is purposely designed to be lined up perfectly with our barrels and gas ports to ensure reliable cycling every time. These Adjustable gas blocks pick up where our standard block leaves off and works perfectly for shooters that want to be able to control their gas flow for suppressed applications.

Out of stock

Out of stock

This Rosco 8.2” 300 Blackout Bloodline Barrel was designed for SBR and Pistol use in conjunction with suppressors. This is the shortest that we will go to allow you the flexibility of a shorter Personal Defense Weapon (PDW) without sacrificing performance or ballistics. ALL NFA RULES APPLY!

Our Rosco 300 Blackout barrels were created by using input from SOCOM end users and some of the original creators of the 300 Blackout caliber. Every barrel was designed to optimize the original role for this caliber; to be suppressor friendly and accurate. It is our goal to get you the performance that you seek out of these AR-15 barrels when running sub-sonic ammo or supersonic ammo (depending on barrel length). Twist rates, gas port diameters, and lengths have all been taken into account when we set out to make these. Let’s just say that we don’t like leaving things to chance.


Barrel Length 8.2″
Barrel Weight 17.73 oz
Barrel Material 4150 CMV
Barrel Caliber 300 BLK
Barrel Profile




Barrel Thread

5/8 x 24

Gas Block Size


Gas System Length

Barrel Crown

11 Degree

Barrel Finish


Barrel Extension Finish


Browse all of our 300 Blackout Bloodline Barrels: 

16″ 300 Blackout Bloodline Barrel
10.5″ 300 Blackout Bloodline Barrel
8.2″ 300 Blackout Bloodline Barrel

Additional information

Weight 1.5 lbs
Dimensions 19.5 × 2.3 × 2.2 in

Melonite Gas Tubes


Pistol Length

7 reviews for Bloodline 8.2″ 300 Blackout Barrel

  1. Alex sharp (verified owner)

    Built an AR pistol with this barrel it ran supers and subs unsuppressed no problem, ran 123gr to 220gr fine no hiccups at all, also came with 1 dimple for a set screw style gas block which was a nice touch, overall look and finish is great. I definitely recommend this product.

  2. Kenneth Wilson (verified owner)

    I ordered this 8.2” 300 BLK barrel, adjustable gas block, gas tube, and BCG all together to install in an Aero Precision M4E1 upper with 9” hand guard. With the Midwest Industries blast diverter, the muzzle is about 1/4” past the hand guard which is what I was going for until I mount a suppressor. Everything went together well and 1” groups at 50 yds with a Trijicon MRO are no issue shooting Fiocchi 125 gr SST. I’m considering temporarily mounting a magnified optic just to aid my eyes in 100 yd accuracy testing. The only negative I’ve experienced so far is that I don’t have last round bolt hold with Remington or Fiocchi subsonic ammunition unsuppressed even with the gas all the way open. However, I’ve only tried a Geissele Super 42 with H1 (which Geissele states may not work) and a cheap buffer and spring I picked up from I forget where. That’s no fault of Rosco and only indicates I need to consult them for a buffer/spring recommendation. I haven’t ran the setup suppressed as of yet either.

  3. Brandon (verified owner)

    Good fit and finish, tight chamber. Haven’t got to play with it too much but easily shoots 3/4″ at 100yds with hornady black 100amax. Can’t beat it for the money.

  4. Todd

    Multiple Roscoe barrels owner, always my GoTO for 300 blackout barrels. Can’t wait to try a 5.56 and if they ever make a gen 5 glock. Started my first with this barrel. Folding takedown and fits in a small camera bag 🔥😅🔥

  5. Mac (verified owner)

    My initial 300 Blk Pistol was built based on the Saint Pistol. It was a 10.5-inch barrel which shot an easy 1.5-inch group with a 4 MOA red dot sight at 50 yards. It shot tighter with a magnified optic. New to builds, I told the gunsmith what I wanted, and he built it with a Rosco Barrel, a company I’d never heard of. That barrel was easy 1.5 MOA at 100 yards. To get the level 2 Cool factor, suppressor under the handguard, I looked for a shorter Rosco Barrel. Out of stock for way too many months. Finally notified, the 8.2 inch was in stock, on sale, and free shipping, so, I ordered it immediately. Testing it today (12-11-21) for 50-yard accuracy. I did check it, indoors, for feed and function, and it was as flawless as the 10.5 Bloodline Rosco. I expect it will prove to be worth the wait. YouTube reviews on Rosco Barrels are most favorable. Price vs performance should leave me smiling, as I am already smiling at how “Level 2,” cool it looks.

  6. Mac (verified owner)

    If you’re new to shooting a new barrel, clean it first. Rosco has no formal break-in for Bloodline Barrels, as they do with the SS series. My gunsmith wanted to run a bunch of tests, but I was in a hurry. I’d waited months for the 8.2 to be in stock. 40-50 rounds of mixed supers and subs, and a bunch of crappy groups, An applications of bore scrubber and the expected accuracy was met. Upped my powder charge from 11.5 to 12.5 from my Bloodline 10.5 and I’m smiling. As expected, price and performance is outstanding.

    The downside to the Rosco 8.2 Bloodline is, it shoots so well, you want to shoot it more. Reloading 300 Blk is not cheap when you shoot it so much. (LOL)

  7. Josh

    Amazing product and crew

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