Rosco Manufacturing K9 5.56 NATO Sage Dynamics Patrol Length AR-15 Barrel - 12.5"

this set up is the best if ever seen when i open the box i knew the barrel was beautiful put it together with vltor upper and strike gridlock lite 11inch perfect shot 200 rounds suppressor and un suppressed flawless also used rosco gas block i will be going to adjustable rosco but it’s great 👍 5 star be careful with that hand guard look at the box

I cant say enough, this barrel is awesome. I just finished my new build and this barrel is just what it needed. I am extremely pleased with this Roscoe 12.5. I am impressed by the accuracy this thing possesses, I was shooting 1" groups at 100 yards with basic 55 grain. I can only imagine when I feed it the 77 grain good stuff, and as always Primary Arms is incredible. Shipping was very fast, received my order in 3 days. I have been a long time customer of P.A. and never think of spending my hard earned money with any other company

As always Rosco delivers. Great manufacturing great products.

I used this barrel on an SBR with a Griffin RECCE suppressor. Everything about it is great, except the barrel dimple leaves a lot to be desired. The depth of the dimple is pretty shallow compared to other barrels I’ve used before. To remedy this I bought a dimple jig and some cobalt drill bits to drill it out some more for more security. I’m at least greatful they put a dimple to begin with, because a lot of these manufacturers don’t do such a valuable thing.

Other than that the accuracy is great, and with a FM adjustable BCG with the suppressor on, I barely got any blowback from the suppressor.

Barrel is good to go. Primary arms is great. Gas port is bigger than I expected. I measured port and then emailed Rosco. Rosco said it’s designed per spec. You will need an adjustable gas block as it is over gassed.

This barrel is extremely nice! I can’t imagine anybody being let down, especially for the price. I haven’t shot it yet, but it is built like a tank and don’t expect any issues.

All the usual- As far as, fit and finish and specs were all good, etc etc. Tested using Vltor A5 Buffer System (up to H2) and a Carbine System up to H3 (H2 recommended)- both options worked great and felt smooth. The rifle had some "thump" to it, but not much muzzle rise (regular A2 birdcage while testing), and re-aquiring the target between shots was not an issue. Weight is to the rear of the barrel, and it's noticable with the balance of the system after adding lights and all that. After 90 rounds, no issues. I was hitting 8" steel at 85 yards before even being zeroed- so accuracy was great as well. Only gripe is that it's stainless, but that's just me and my preference for 4150. Get it if you've been looking at it- it was worth it.

I built a 12.5" patrol length upper using the Rosco K9 barrel, gas block, gas tube and BCG. All on a Aero Precision M4e1 receiver set, Midwest Ind. 11" slim handguard, Griffin Armament taper mount 2 part brake and their suppressor normalized advanced charging handle (SN-ACH).
It all ran great, with almost no recoil, was spot-on accurate at 50yds. Ran without a hiccup, suppressed or unsuppressed.
I'm a total believer in this patrol length system.
😎 👍