Rosco Manufacturing K9 12.5″ Sage Dynamics 5.56 NATO

MSRP: $185.00
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(4 customer reviews)

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Frequently Bought Together

Price for both: Original price was: $210.99.Current price is: $168.79.

The K9 12.5  from Rosco Manufacturing offers a proprietary patrol length gas system that is smoother than carbine length, more reliable than mid-length. Features an optimized gas port to run reliably suppressed and/or unsuppressed. The K9 continuous taper is the most effective profile to dissipate heat from hard use. With weight shifted to the back of the barrel, modern attachments on the front of the rifle create a perfectly balanced and better handling rifle. Updated target crown carried over from the Purebred series. Features no 90 degree cuts, improved harmonics, fit and finish.


Barrel Length 12.5″
Barrel Weight 27.05 oz
Barrel Material 416R
Barrel Caliber 5.56
Barrel Profile




Barrel Thread

1/2 x 28

Barrel Gas Block Size


Gas System Length

Barrel Crown

11 Degree

Barrel Finish


Barrel Extension Finish



Additional information

Weight 27 oz
Dimensions 14 × 5 × 4 in

4 reviews for Rosco Manufacturing K9 12.5″ Sage Dynamics 5.56 NATO

  1. Ramon Santana Vazquez (verified owner)

    Best barrel i ever used!

  2. Anthony Gutierrez (verified owner)

    Great barrel. Great company making them. Can’t wait to shoot it.

  3. emmagee (verified owner)

    This is my go-to barrel for AR Pistol. Such a smooth action with the SOLGW 9-position A5 receiver extension. I’ll buy this again.

  4. Zach1 (verified owner)

    If you are on the fence about this barrel I recommend just getting it. They definitely did their homework on this one. It is surprisingly accurate for the price range. It is very enjoyable, light recoiling, and smooth to shoot paired with a green Sprinco and A5H2. While the barrel “feels” heavy alone it balances out to feel lighter than other comparable length guns. Even with a light and suppressor on it I still find myself preferring this one more than my usual favorite. I will probably end up with more of these barrels. As a side note that isn’t necessary, but still a nice touch, Rosco’s packaging is also much more over the top than you would expect. I definitely recommend this barrel.

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